Question

Ellason wants to solve the following system using the elimination method: 5x + 2y = 30 x + y = 8 What number should the equation x + y = 8 be multiplied by to eliminate y?

2, −2, 5, −5

Answer 1

-2.
5x + 2y = 30
-2x- 2y = 16
3x = 14

Answer 2

- 2 because we obtain : - 2x - 2y = - 16 ;
We solve the system:
5x + 2y = 30
-2x - 2y = -16
_____________(+)
3x / = 14;
x = 14/3;
y = 8 - 14/3;
y = 24/3 -14/3;
y = 10/3;

The solution of the system is ( 14/3 ; 10/3 )