(150-10x)(40-30+x)=1560
(150-10x)(10+x)=1560
1500+150x-100x-10x^2=1560
10x^2-50x+60=0
x^2-5x+6=0
你算错了吧
(x-2)(x-3)=0
x1=2
x2=3.