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解下列方程:(1)x2+4x-5=0 (2)(2x-3)2-5(...

(1)a=1,b=4,c=-5∴△=16+4×5=36>0∴x=?4±362∴x1=-5,x2=1;(2)设2x-3=y,则原方程可化为:y2-5y+6=0,∴y=5±25?242∴y1=2,y2=3.当y1=2时,2x-3=2,x1=52;当y2=3时,2x-3=3,x2=3.∴x1=52,x2=3.(3)方程两边同乘x(x-1),得3(x-1)+2x=...

(1)分解因式得:(x-1)(x+5)=0,可得x-1=0或x+5=0,解得:x1=1,x2=-5;(2)分解因式得:(2x-5+x+4)(2x-5-x-4)=0,解得:x1=13,x2=9;(3)方程移项得:5(x+2)-4x(x+2)=0,分解因式得:(5-4x)(x+2)=0,解得:x1=54,x2=-2;...

(1)(4x+3)(5-x)=0 x=-3/4 x=5 (2)(x-1)^2+2x(x-1)=0 (x-1)(x-1+2x)=0 x=1 x=1/3 (3)2x^2-4x-5=0 x=4+√16+4*2*5/2*2=4+√56/4=2+√14/2 或x=4-√16+4*2*5/2*2=4-√56/4=2-√14/2 (4)-3x^2-4x-5=0 判别式=16-4*3*5

(1)把方程直接开平方得:x-5=±4,∴x 1 =-5-4=-9,x 2 =4-5=-1;(2)a=1,b=-4,c=1,∴x= -b± b 2 -4ac 2a = 4± 16-4 2 = 4± 2 3 2 =2± 3 ;(3)a=1,b=-4,c=5,∵△=b 2 -4ac=16-20=-4<0,∴次方程无解.(4)a=1,b=5,c=3,∴x= -b± b 2 -4...

(1)x2+4x-5=0,(x-1)(x+5)=0,∴x1=1,x2=-5;(2)(2x-3)2-5(2x-3)=-6;∴(2x-3)2-5(2x-3)+6=0,(2x-3-2)(2x-3-3)=0,∴x1=2.5,x2=3;(3)(x-1)(x+2)=70,∴x2+2x-x-2-70=0,x2+x-72=0,(x-8)(x-9)=0,∴x1=8,x2=9;(...

2(x-5)2-(x-5)=0,(x-5)(2x-10-1)=0,解得:x1=5,x2=112.(2)原方程可化为:(x-8)(x+4)=0,解得:x1=8,x2=-4.(3)原方程可化为:x2+6x+9-2x-5=0,(x+2)2=0,解得:x=-2.(4)原方程可化为:2x2-6x+x-3=-6,2x2-5x+3=0,解...

(1)(x+2-5)(x+2+5)=0,所以x1=3,x2=-7;(2)x2+4x=5,x2+4x+4=9,(x+2)2=9,x+2=±3,所以x1=1,x2=-5;(4)x(x+3)-2(x+3)=0,(x+3)(x-2)=0,所以x1=-3,x2=2;(5)△=(-7)2-4×2×1=41,x=7±412×2所以x1=7+414,x2=7?414.

(1)方程变形得:(x-2)2=4,开方得:x-2=2或x-2=-2,解得:x1=0,x2=4;(2)方程移项得:3(x-2)2-x(x-2)=0,分解因式得:(x-2)(2x-6)=0,解得:x1=2,x2=3;(3)分解因式得:(x-1)(x+5)=0,解得:x1=1,x2=-5;(4)方程变形得...

(1)a=1,b=4,c=-5∴△=16+4×5=36>0∴x= -4± 36 2 ∴x 1 =-5,x 2 =1;(2)设2x-3=y,则原方程可化为:y 2 -5y+6=0,∴y= 5± 25-24 2 ∴y 1 =2,y 2 =3.当y 1 =2时,2x-3=2,x 1 = 5 2 ;当y 2 =3时,2x-3=3,x 2 =3.∴x 1 = 5 2 ,x 2 =3.(3...

(1)2x 2 -5=4x,2x 2 -4x=5,x 2 -2x= 5 2 ,x 2 -2x+1= 5 2 +1,(x-1) 2 = 7 2 ,x=± 14 2 +1,x 1 = 14 2 +1,x 2 =- 14 2 +1;(2)x 2 -4x+1=0,x 2 -4x=-1,x 2 -4x+4=-1+4,(x-2) 2 =3,x-2= ± 3 ,x 1 = 3 + 2,x 2 =- 3 + 2;(3...

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