Question

30+x+90=180 como resolver

Answer 1

$30+x+90=180 \\ x+90=180-30 \\ x=180-30-90 \\ x=180-120 \\ x=60$

Bons estudos!

Answer 2

30+x=180-90 ( troca o lado mudando o sinal)
x=180-90-30
x=60