Question

Podem me ajudar a fazer essa ?

Answer 1

{x+y=15 (1)

{2x+3y=21 (2)

1) x+y=15

x=15-y

x=15-(-9) .(-1)

x=15+9

x= 24

2) 2.(15-y)+3y=21

30-2y+3y=21

30+y=21

y=21-30

y= -9

(24,-9)