(1)1/5(x+3)²=5
x+3 ²= 25
x+ 3 = ±5
x = 2或者 -8
（2）x³+1=7/8
x³ = -1/8
x = -1/2要过程！(1)1/5(x+3)²=5(x+3 )²= 25x+ 3 = ±5x+3=5或者x+3 = -5x = 2或者 -8（2）x³+1=7/8x³ = -1/8x =立方根(-1/8)= -1/2