解方程 (1)x2-5x-24=0 (2)7x(5x+2)=6(5x+2) (3)x2+12x+25=0 (4)5x+2=3x2.
问题描述:
解方程
(1)x2-5x-24=0
(2)7x(5x+2)=6(5x+2)
(3)x2+12x+25=0
(4)5x+2=3x2.
答
(1)∵x2-5x-24=0∴(x-8)(x+3)=0,解得:x=8,或x=-3,(2)∵7x(5x+2)=6(5x+2)∴(7x-6)(5x+2)=0,解得:x=67,或x=-25,(3)∵x2+12x+25=0∴x=−12±122−4×252=−6±11,∴x=−6+11,或x=−6−11,...