习题2.3 (1)x^2+12x+25=0 (2)x^2+4x=10 (3)x^2-6x=11 (4)x^2-2x-4=0
问题描述：
习题2.3 (1)x^2+12x+25=0 (2)x^2+4x=10 (3)x^2-6x=11 (4)x^2-2x-4=0
答
(1)x^2+12x+25=0 x1,2=[-12±√(12^2-4*25)]/2=-6±√11(2)x^2+4x=10x^2+4x-10=0x1,2=[-4±√(4^2-4*(-10))]/2=-2±√14(3)x^2-6x=11 x^2-6x-11=0x1,2=[6±√(6^2-4*(-11))]/2=3±2√5(4)x^2-2x-4=0x1,2=[2±√(2^2-...