Question

{ x + y = 20
{ 3x + 4y = -2

(A) x=12 e y=8
(B) x=10 e y=10
(C) x=8 e y=12
(D) x=9 e y=11
(E) x=15 e y=5

Answer 1

x=20-y
3(20-y) + 4y = (-2)
60- 3y+ 4y= (-2)
60 + y= (-2)
y= -2-60
y= -62.
x=20-y <=> x=20-(-62) <=> x=82.
Espero ter ajudado