20+20(x+1)+20(x+1)²=95.
问题描述:
20+20(x+1)+20(x+1)²=95.
答
20+20(x+1)+20(x+1)²=95
1+(x+1)(x+1)²=4.75
x²+3x-1.75=0
(x+3.5)(x-0.5)=0
x=-3.5 x=0.5