(90+2x)(40+2x)X0.72=3600一元二次方程怎么解各位帮帮忙急!

问题描述:

(90+2x)(40+2x)X0.72=3600一元二次方程怎么解各位帮帮忙急!

(90+2x)(40+2x)X0.72=3600
(90+2x)(40+2x)=5000
3600+80x+180x+4x^2=5000
4x^2+260x=1400
x^2+65x-350=0
(x+70)(x-5)=0
x1=-70 x2=5