Question

(1)x^2-根号2x-1/4=0 (2) X(X-4)=2-8X (3) X^2+2根号5x+10=0

用公式法解下列方程

Answer 1

1.
x^2-√2 x +1/2 -1/2-1/4=0
(x-(√2)/2)^2 -3/4=0
(x-(√2)/2)^2=3/4
x-(√2)/2=±(√3)/2
x1=（√3+√2）/2
x2=（-√3+√2）/2

2.
x^2-4x=2-8x
x^2+4x+4=2+4
(x+2)^2=6
x+2=±√6
x1=√6-2
x2=-√6-2

3.
x^2+2√5x+10=0
x^2+2√5x+5+10=5
x^2+2√5x+5=-5
（x+√5）^2=-5
无解