Question

What is the value of y in the following system? 5x + y = 9
10x - 7y = -18

Answer 1

y = 4

Explanation:

given the 2 equations

5x + y = 9 → (1)

10x - 7y = - 18 → (2)

Multiplying (1) by - 2 and adding to (2) will eliminate the term in x

- 10x - 2y = - 18 → (3)

Add (2) and (3) term by term on both sides

(10x - 10x) + (-7y - 2y) = (- 18 - 18)

0 - 9y = - 36

- 9y = - 36 ( divide both sides by - 9 )

y = 4

Answer 2

y = 4

Explanation:

We have given a system of equation.

5x+y = 9 eq(1)

10x-7y = -18 eq(2)

We have to find the value of y.

Multiplying eq(1) by 2 , we have

10x+2y = 18

Subtracting above equation from eq(2) , we have

10x+2y-(10x-7y) = 18-(-18)

10x+2y-10x+7y = 18+18

9y = 36

y = 4 which is the answer.