Question

(50-x-30)(100+20X)=3000 解方程

Answer 1

即(20-x)*20(x+5)=3000

两边除以-20

(x-20)(x+5)=-150

x²-15x-100=-150

x²-15x+50=0

(x-5)(x-10)=0

x=5,x=10