Question

resolvendo o sistema encontramos (se der botem calculo.bjjs)

A)S=[(-7,-13)] C)S=[(3,8)]
B)S=[(9,1)] D)S=[(7,13)]$\left \{ {{2x+y=21} \atop {3x-y=34}} \right.$

Answer 1

2x + y = 21

3x - y = 34

5x = 55

x = 55/5     x = 11

2.11 + y  = 21

y = 21 - 22

y = -1

x = 11  e y  = - 1