(1)x²-34=0
x²=34
x=±√34
(2)4x²=16x
4x²-16x=0
4x(x-4)=0
x1=0
x2=4
(3)3x²-12=0
3x²=12
x²=4
x1=2
x2=-2
(4)x²+3x=0
x(x+3)=0
x1=0
x2=-3
(5)求(a-b)²+4ab
=a²-2ab+b²+4ab
=a²+2ab+b²
=(a+b)²
(1)x²-34=0
x²=34
x=±√34
(2)4x²=16x
4x²-16x=0
4x(x-4)=0
x1=0
x2=4
(3)3x²-12=0
3x²=12
x²=4
x1=2
x2=-2
(4)x²+3x=0
x(x+3)=0
x1=0
x2=-3
(5)求(a-b)²+4ab
=a²-2ab+b²+4ab
=a²+2ab+b²
=(a+b)²