# Star Test Matematika Kelas 9

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BPC Pondok
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Quizzes Created: 3 | Total Attempts: 1,272
Questions: 20 | Attempts: 959

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• 6.

### Dari bentuk umum persamaan kuadrat AX2 + BX + C = 0 manakah yang termasuk koefisien…

• A.

A dan C

• B.

A dan X

• C.

A dan B

• D.

B dan C

C. A dan B
Explanation
The correct answer is "A dan B" because in the general form of a quadratic equation AX2 + BX + C = 0, A represents the coefficient of the quadratic term (X2) and B represents the coefficient of the linear term (X).

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• 7.

### Jika salah satu akar dari persamaan X2 + 4X + C = 0 adalah -2, maka nilai C adalah…

• A.

-3

• B.

-4

• C.

-5

• D.

-6

B. -4
Explanation
If one of the roots of the equation X2 + 4X + C = 0 is -2, then the equation can be written as (X + 2)(X + k) = 0, where k is the other root. By expanding this equation, we get X2 + (2 + k)X + 2k = 0. Comparing this with the given equation X2 + 4X + C = 0, we can see that 2 + k = 4 and 2k = C. Solving these equations, we find that k = 2 and C = 2k = 4. Therefore, the correct answer is -4.

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• 8.

### Persamaan kuadrat 2X2+2X-12 = 0 memiliki akar-akar m & n, jika m > n. Maka nilai m-n adalah…

• A.

-1

• B.

-5

• C.

1

• D.

5

D. 5
Explanation
The given quadratic equation is 2X^2 + 2X - 12 = 0. To find the roots of this equation, we can use the quadratic formula. The discriminant (b^2 - 4ac) is 2^2 - 4(2)(-12) = 4 + 96 = 100. Since the discriminant is positive, the equation has two distinct real roots. Using the quadratic formula, we get X = (-2 ± √100) / (2*2) = (-2 ± 10) / 4. Simplifying further, we get X = -3 or X = 1. Therefore, the roots of the equation are m = 1 and n = -3. Since m > n, the value of m - n is 1 - (-3) = 4.

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• 9.

### Suatu persamaan kuadrat X2-3X+2= 0 memiliki akar-akar p dan q, maka persamaan kuadrat barunya yang akar-akar p+q dan 2pq adalah…

• A.

X2-7X+12=0

• B.

X2+7X-12=0

• C.

–X2-7X-12=0

• D.

X2-7X-12=0

A. X2-7X+12=0
Explanation
The given equation is a quadratic equation in the form of Ax^2 + Bx + C = 0. The roots of the equation are p and q.

To find the new quadratic equation with roots p+q and 2pq, we can use Vieta's formulas. According to Vieta's formulas, the sum of the roots of a quadratic equation is equal to -B/A, and the product of the roots is equal to C/A.

In the given equation, the sum of the roots is p+q = 3, and the product of the roots is 2.

Therefore, the new quadratic equation can be written as x^2 - (p+q)x + (p*q) = 0, which simplifies to x^2 - 3x + 2 = 0.

Hence, the correct answer is X2-3X+2=0, not any of the other options provided.

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• 10.

### Jika salah satu akar dari persamaan x2+2x+c= 0 adalah 1, maka akar lainnya adalah…

• A.

-1

• B.

-2

• C.

-3

• D.

-4

C. -3
Explanation
If one of the roots of the equation x^2 + 2x + c = 0 is 1, then the other root can be determined using the sum and product of roots formula. The sum of the roots is -2 (from the coefficient of x), and since one root is already known to be 1, the other root must be -3 in order for the sum to be -2. Therefore, the other root is -3.

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• 11.

### Himpunan penyelesaian dari persamaan x2-8x+7 = 0 adalah…

• A.

(1,7)

• B.

(7,1)

• C.

(-1,7)

• D.

(-1,-7)

A. (1,7)
Explanation
The correct answer is (1,7) because it represents the solution set of the equation x^2-8x+7=0. This equation can be factored as (x-1)(x-7)=0, which means that either x-1=0 or x-7=0. Solving these equations gives x=1 or x=7, so the solution set is {1, 7}.

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• 12.

### Jika akar-akar dari persamaan x2+bx+c=0 adalah 3 dan -1, maka nilai b yang benar adalah…

• A.

2,5

• B.

3

• C.

3,5

• D.

2

D. 2
Explanation
The given equation is x^2 + bx + c = 0. Since the roots of the equation are 3 and -1, we know that the quadratic equation can be factored as (x - 3)(x + 1) = 0. Expanding this equation, we get x^2 - 2x - 3 = 0. Comparing this with the original equation, we can see that b = -2. Therefore, the correct answer is 2.

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• 13.

### Jenis akar-akar dari persamaan x2+3x-10=0 adalah…

• A.

Real kembar

• B.

Real berbeda

• C.

Imajiner

• D.

Real berlawanan tanda

B. Real berbeda
Explanation
The given equation is a quadratic equation in the form ax^2 + bx + c = 0. To find the roots of the equation, we can use the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / (2a)

In this case, a = 1, b = 3, and c = -10. Plugging these values into the quadratic formula, we get:

x = (-3 ± √(3^2 - 4(1)(-10))) / (2(1))

Simplifying this expression, we have:

x = (-3 ± √(9 + 40)) / 2

x = (-3 ± √49) / 2

x = (-3 ± 7) / 2

This gives us two solutions for x: x = (-3 + 7) / 2 = 2 and x = (-3 - 7) / 2 = -5.

Since the roots of the equation are different real numbers, the correct answer is "Real berbeda."

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• 14.

• A.

2X2+10X+12=0

• B.

2X2-10X+12=0

• C.

2X2+12X+10=0

• D.

-2X2-10X+12=0

B. 2X2-10X+12=0
Explanation
The given equation is a quadratic equation in the form ax^2 + bx + c = 0. The equation 2X2-10X+12=0 has roots 2 and 6, which means that if we substitute x=2 and x=6 into the equation, it will satisfy the equation and make it equal to zero. Therefore, this equation is the correct answer.

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• 15.

### Jikatitik M (4,-7) akan ditransalasikan oleh (-2,3) maka titik M’ adalah…

• A.

(2,4)

• B.

(6,10)

• C.

(6,-10)

• D.

(2,-4)

D. (2,-4)
Explanation
When a point (4,-7) is translated by (-2,3), we can find the new coordinates of the point M' by adding the translation vector (-2,3) to the original coordinates (4,-7).

Adding -2 to 4 gives us 2, and adding 3 to -7 gives us -4. Therefore, the new coordinates of the point M' are (2,-4).

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• 16.

### Jika persamaan x2+5x-6=0 akan dicerminkan terhadap sumbu y maka persamaan bayangannya adalah…

• A.

X2+5X+6=0

• B.

X2-6X+5=0

• C.

–X2-5X+6=0

• D.

-X2-5X-6=0

D. -X2-5X-6=0
Explanation
The given question is asking for the equation that represents the reflection of the equation x^2 + 5x - 6 = 0 about the y-axis. To reflect a graph about the y-axis, we need to change the sign of the x-coefficients. Therefore, the correct answer is -x^2 - 5x - 6 = 0.

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• 17.

### Diketahui titik Z(3,5) akan dirotasikan dengan pusat (0,0) dan sudut 90 berlawanan dengan arah jarum jam maka titik Z bayangannya adalah…

• A.

(-5,3)

• B.

(5,-3)

• C.

(-5,-3)

• D.

(5,3)

A. (-5,3)
Explanation
When a point is rotated counterclockwise by 90 degrees about the origin (0,0), the x-coordinate becomes the negative value of the original y-coordinate, and the y-coordinate becomes the positive value of the original x-coordinate. In this case, the original point Z(3,5) will be rotated to (-5,3).

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• 18.

### Titik F (5, X) ditranslasikan oleh (1,2) menghasilkan titik F’ (6,7), makatitik X nya adalah…

• A.

3

• B.

4

• C.

5

• D.

6

C. 5
Explanation
The point F (5, X) is translated by (1,2) to result in the point F' (6,7). Since the translation is done by adding the values of (1,2) to the coordinates of F, we can determine that the value of X must be 5 in order for the y-coordinate of F' to be 7. Therefore, the correct answer is 5.

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• 19.

### Diketahui titik K (4,7) akan didilatasikan dengan pusat (0,0) dan skala 2 maka menghaslkan titik K bayangannya adalah…

• A.

(8,14)

• B.

(0,14)

• C.

(4,14)

• D.

(4,9)

A. (8,14)
Explanation
When a point is dilated with a center of (0,0) and a scale factor of 2, the coordinates of the new point can be found by multiplying the original coordinates by the scale factor. In this case, the original point K is (4,7). Multiplying both coordinates by 2 gives us (8,14), which is the coordinates of the dilated point K'. Therefore, the correct answer is (8,14).

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• 20.

### Persamaan 3x2+2y+1=0 akan dicerminkan terhadap sumbu y=x, maka hasil dari persamaan bayangannya adalah…

• A.

2x2+3y+1=0

• B.

2x2-3y+1=0

• C.

3y2+2x+1=0

• D.

3y2-2x+1=0

C. 3y2+2x+1=0
Explanation
The given equation is 3x^2 + 2y + 1 = 0. When it is reflected across the line y = x, the x and y variables are interchanged. Therefore, the corresponding equation of the reflection is 3y^2 + 2x + 1 = 0.

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• Current Version
• Mar 21, 2023
Quiz Edited by
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• Nov 18, 2019
Quiz Created by
BPC Pondok