Question

How to solve this with the elimination method:

4x + 7y = 60
-4x + 7y = -4

 

Answer 1

Elimination method

Given equations are 4x+7y = 60 ----------> (1)

-4x+7y = -4 ---------> (2)

To eliminate the x value, add the equations (1) and (2).

4x+7y = 60

-4x+7y = -4

__________

14y = 56

Divide to each side by 14.

14y/14 = 56/14

y = 4

Substitute the y value in (1).

4x+7*4 = 60

4x+28 = 60

Subtrac 28 from each side.

4x+28-28 = 60-28

4x = 32

Divide to each side by 4.

4x/4 = 32/4

x = 8

Solution x = 8, y = 4.