1.4x^2+12x-16=0
x^2+3x-4=0
(x+4)(x-1)=0
x=-4,x=1
2.x^2+14x+49=3x^2+21x
2x^2+7x-49=0
(2x-7)(x+7)=0
x=2/7,x=-7
因为0没有平方,所以x=2/7
3,4(x^2-4x+4)-x^2+4=0
3x^2-16x+20=0
(x-2)(3x-10)=0
x=2,x=3/10
4,x^2+2x-3x-6-6=0
x^2-x-12=0
(x-4)(x+3)=0
x=4,x=-3
1.4x^2+12x-16=0
x^2+3x-4=0
(x+4)(x-1)=0
x=-4,x=1
2.x^2+14x+49=3x^2+21x
2x^2+7x-49=0
(2x-7)(x+7)=0
x=2/7,x=-7
因为0没有平方,所以x=2/7
3,4(x^2-4x+4)-x^2+4=0
3x^2-16x+20=0
(x-2)(3x-10)=0
x=2,x=3/10
4,x^2+2x-3x-6-6=0
x^2-x-12=0
(x-4)(x+3)=0
x=4,x=-3