`320:(x-1)=(5^3 - 5^2):4+15`

`320:(x-1)=100:4+15`

`320:(x-1)=25+15`

`320:(x-1)=40`

`x-1=320:40`

`x-1=8`

`x=8+1`

`x=9`

Vậy `x=9`

`b)`

`75:(x+2)=5^3 - (3^2 +4^2).2^2`

`75:(x+2)=125-25.4`

`75:(x+2)=125-100`

`75:(x+2)=25`

`x+2=75:25`

`x+2=3`

`x=3-2`

`x=1`

Vậy `x=1`

`c)`

`260:(x+4)=5(2^3 +5)-3(3^2 +2^2)`

`260:(x+4)=5(8+5)-3(9+4)`

`260:(x+4)=5.13-3.13`

`260:(x+4)=13(5-3)`

`260:(x+4)=13.2`

`260:(x+4)=26`

`x+4=260:26`

`x+4=10`

`x=10-4`

`x=6`

Vậy `x=6`

`d)` 

`(2^3 +3)(x-5)+14=5^2+124 :2^2`

`(8+3)(x-5)+14=25+124:4`

`11(x-5)+14=25+31`

`11(x-5)+14=56`

`11(x-5)=56-14`

`11(x-5)=42`

`x-5=42:11`

`x-5=42/11`

`x=42/11+5`

`x=97/11`

Vậy `x=97/11`

`e)`

`3^2 (x+1)-3=2^3 +(7^2 .2):14`

`9(x+1)-3=8+(49.2):14`

`9(x+1)-3=8+98:14`

`9(x+1)-3=8+7`

`9(x+1)-3=15`

`9(x+1)=15+3`

`9(x+1)=18`

`x+1=18:9`

`x+1=2`

`x=2-1`

`x=1`

Vậy `x=1`

`f)`

`2^2 . 3(x+5)-6^2=(2^3+2^2) .2^2`

`4 .3(x+5)-36=(8+4).4`

`12(x+5)-36=12.4`

`12(x+5)-36=48`

`12(x+5)=48+36`

`12(x+5)=84`

`x+5=84:12`

`x+5=7`

`x=7-5`

`x=2`

Vậy `x=2`