\(a,223-6\left(x+5\right)=49\\ 6\left(x+5\right)=223-49\\ 6\left(x+5\right)=174\\ x+5=174:6\\ x+5=29\\ x=29-5\\ x=24\\ ----\\ b,4x^3+12=120\\ 4x^3=120-12\\ 4x^3=108\\ x^3=108:4\\ x^3=27\\ Mà:3^3=27\\ Nên:x^3=3^3\\ Vậy:x=3\)
a. 223 - 6. (x + 5) = 49
6. (x + 5) = 223 - 49
6. (x + 5) = 174
x + 5 = 174 : 6
x + 5 = 29
x = 29 - 5
x = 24
b. 4x3 + 12 = 120
4x3 = 120 - 12 = 108
x3 = 108 : 4 = 27
x3 = 33
x= 3