Question

X+3y+7=0
2x-y+7=0
Busca el valor de x y el valor de y

Answer 1

x=-1

y=-4

Explanation:

x+3y=-7

2x-y=-7

make x the subject of the formula

x=-7-3y––––equation i

substitute for x in equation ii

2(-7-3y)-y=-7

-14-6y-y=-7

-7y=-7+14

-7y=7

divide both sides by -7

-7y/-7=7/-7

y=-1

substitute for y in equation i

x+3(-1)=-7

x=-7+3

x=--4