把35分解成5*7,12分解成2*6,即 5 2
7 -6
5*(-6)=-30,2*7=14,14+(-30)=-16,故分解成(5x+2)(7x-6)=0
35x^2-16x-12=0
(5x-6)(7x+2)=0
x1=6/5 x2=-2/7
(5X+2)(7x-6)=0
(5X+2)(7X-6)=0
35x^2-16x-12=(7x-6)(5x+2)=0
x1=6/7,x2=-2/5