Question

What is the value of y in the system of equations shown below?

7x − 7y = 49
3x − 16y = 34

Select one:
A. -2
B. -1
C. 0
D. 1

Answer 1

B. -1

Explanation:

Given

`7x-7y =49\\7(x-y)=49\\x-y =(49)/(7)\\x-y= 7 \ \ \ \ equation \ 1`

`3x- 16y = 34 \ \ \ \ equation \ 2`

Now multiplying equation 1 with 3 on both side we get,

`3* (x-y)= 3 * 7\\3x-3y=21 \ \ \ \ \ equation \ 3`

Now Subtracting above equation 3 from equation 2 we get.

`-13y=13\\y= -1`