题目

(要详细的过程)用公式法解下列方程：(1) x^2+x-12=0 ; (2)x^2-√2（x）-1/4=0 ; (3) x^2+4x+8=2x+11
(4) x ( x - 4) = 2 - 8x ; (5) x^2+2x=0 ;
(6) x^2+2√5(x)+10=0.

提问时间：2020-08-03

答案

(1) x^2+x-12=0 => (x+4)(x-3)=0 => x1=-4,x2=3(2) x^2-√2（x）-1/4=0 => x^2-√2(x)+ [(√2)/2]^2-[(√2)/2]^2-1/4=0=> [x-(√2)/2]^2-1/2-1/4=0 => [x-(√2)/2]^2=3/4 => x=±(√3)/2+(√2)/2=> x1=(√3-√2)/2,x...