Question

Which statement correctly explains how Mari should find a solution to the following system of linear equations using elimination?

2f-5g=-9
-7f+3g=4

Multiply the first equation by 7 and the second equation by 2, and then add.
Multiply the first equation by 3 and the second equation by 5, and then subtract.
Multiply the first equation by –7 and the second equation by 2, and then add.
Multiply the first equation by –3 and the second equation by 5, and then add.

Answer 1

Multiply the first equation by 7 and the second equation by 2, and then add.

Explanation:

Answer 2

Multiply the first equation by 7 and the second equation by 2, and then add.

Explanation:

2f - 5g=-9

-7f + 3g=4

To eliminate any variable , we need to make the coefficients same with different sign and add it

the coefficient of 'f' in first equation is 2

the coefficient of 'f' in second equation is -7

We already have different sign so we make the coefficients same

To make the coefficient same , we multiply the first equation by 7 and second equation by 2

So equation becomes

14f - 35g = -63

-14f + 6g = 8

Now when we add both equations, 'f' gets cancelled

-29g = -55