Question

1)Resolva: a){3x+3y=21/{2x-y=5

Answer 1

Resposta:

x=4  y=3

Explicação passo-a-passo:

$\left \{ {{3x+3y=21} \atop {2x-y=5}} \right.\\\left \{ {{y=2x-5} \atop {3x+3.(2x-5)=21}}\\\left \{ {3x+6x-15=21{} \atop {9x=36\left \{ x=4}$$\left \{ {{y=2.(4)-5=3}$