Question

7x+20=2(3x+1) e 9x=20+8(x-1) são numeros opostos

Answer 1

a)
7x + 20 = 2.(3x + 1)
7x + 20 = 6x + 2
7x - 6x = 2 - 20
x = - 18
================================
b)
9x = 20 + 8.(x - 1)
9x = 20 + 8x - 8
9x - 8x = 20 - 8
x = 12