Tìm x : a) (x – 29) – 11 = 0. b) (x + 5) : 3 – 11 = 4. c, 231 + (312 – 2x) = 531

Tìm x
a, (x–29)–11=0
b, (x+5):3–11=4
c, 231+(312–2x)=531