Question

Please give a sure answer:) 30 pts

To solve this system of equations by elimination, what operation could be used to eliminate the y-variable and find the value of x?


6x + 5y = 2

4x + 2y = 8

A) subtract 2 times the second equation from 3 times the first equation

B) subtract 3 times the second equation from 2 times the first equation

C) subtract 5 times the second equation from 2 times the first equation

D) subtract 2 times the second equation from 5 times the first equation

Answer 1

C) subtract 5 times the second equation from 2 times the first equation

Explanation:

We want to eliminate the y variable so the coefficients have to be the same and opposite

6x + 5y = 2

4x + 2y = 8

Multiply the first equation by 2 and the second equation by 5. Then subtract the second equation from the first

2(6x + 5y) = 2*2

12x +10y = 4

5( 4x + 2y) = 8*5

20x + 10y = 40

12x +10y = 4

-( 20x + 10y = 40)

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-8x = -36