Tìm x a/ 1/3 + 2/3 : x = -1 2/3 b/ 1/2 - 2(x + 3/4) = 5/6

Tìm x

a/ 13+23:x=−123

b/ 12−2.x+34=56

c/ x2+x3=−1

d/ 3x−1=2116