Question

3x+y=5 , 2x-2y=22 solve the system of equations by the addition method

Answer 1

3x+y=5

2x-2y=22 ...............2(x-y)=22 ⇒ x-y=11

3x+y=5

x-y=11                   (+)

3x+x+y-y=11+5

4x=16  /:4

x=4

x-y=11

4-y=11

-y=7 /*(-1)

y=-7

Answer 2

$3x+y=5\\ 2x-2y=22\\\\ 3x+y=5\\ \underline{x-y=11}\\ 4x=16\\ x=4\\\\ 4-y=11\\ -y=7\\ y=-7\\\\ \boxed{(x,y)=(4,-7)}$