急用!解一元二次方程。能用因式分解就用因式分解!谢谢!

2024-12-27 11:27:40
推荐回答(4个)
回答1:

①(6y+5)(6y-5)-24=0
(6y)²-5²-24=0
(6y)²-25-24=0
(6y)²-49=0
(6y+7)(6y-7)=0
y1=-7/6, y2=7/6

②4(x-3)²-x(x-3)=0
4x²-24x+36-x²+3x=0
3x²-21x+36=0
(3x-9)(x-4)=0
x1=3, x2=4

③(x+4)²-(2x-1)=0
(x+4+√(2x-1))(x+4-√(2x-1))=0

④(2t+3)²=3(2t+3)
2t+3=3
t=0

⑤(3-y)²+y²=9
(3-y)²=9-y²=(3-y)(3+y)
(3-y)=(3+y)
y=0

⑥(1+√2)x²-(1-√2)x=0
x((1+√2)x-(1-√2))=0
x1=0
(1+√2)x-(1-√2)=0
(1+√2)x=(1-√2)
x2=(1-√2)/(1+√2)

⑦x²=x+56 必须用因式分解
x²-x-56=0
(x-8)(x+7)=0
x1=8, x2=-7

⑧x-2=x(x-2) 必须用因式分解
x-2=x²-2x
x²-3x+2=0
(x-1)(x-2)=0
x1=1, x2=2

⑨x(5x+4)=5x+4 必须用因式分解
5x²+4x=5x+4
5x²-x-4=0
(5x+4)(x-1)=0
x1=-4/5, x2=1

⑩(x-1)(x+2)=70
x²+x-2=70
x²+x-72=0
(x+9)(x-8)=0
x1=-9, x2=8

⑴(x+1)²+2x(x-1)=0
x²+2x+1+2x²-2x=0
3x²+1=0
x²=-1/3
x1=√(-1/3), x2=-√(-1/3)

⑵(x+1)²-3(x+1)+2=0
x²+2x+1-3x-3+2=0
x²-x=0
x1=0, x2=1

⑶(x-2)²=(2x+3)²
(x-2)²-(2x+3)²=0
((x-2)+(2x+3))((x-2)-(2x+3))=0
(x-2+2x+3)(x-2-2x-3)=0
(3x+1)(-x-5)=0
x1=-1/3, x2=-5

⑷(2x+3)²=4(2x+3)
(2x+3)²-4(2x+3)=0
((2x+3)-4)(2x+3)=0
(2x-1)(2x+3)=0
x1=1/2, x2=-3/2

⑸2(x-3)²=x²-9
2(x-3)²=(x+3)(x-3)
2(x-3)²-(x+3)(x-3)=0
(2(x-3)-(x+3))(x-3)=0
(2x-6-x-3)(x-3)=0
(x-9)(x-3)=0
x1=9, x2=3

回答2:

1.36y²-25-24=0
(6y-7)(6y+7)=0
2.(x-3)[4(x-3)-x]=0
(x-3)(4x-12-x)=0
3(x-3)(x-4)=0
3.x²+8x+16-2x+1=0
x²+6x+17=0
△=6²-17*4*1<0,无法分解,故为无解
4.(2t+3)[(2t+3)-3]=0
2t(2t+3)=0
5.2y²-6y+9-9=0
2y(y-3)=0
6.x²+√2x²-x+√2x=0
(x+√2x-1+√2)x=0
7.x²-x-56=0
(x-8)(x+7)=0
8.x-2-x(x-2) =0
(x-2)(1-x)=0
(x-2)(x-1)=0
9.x(5x+4)-5x+4 =0
(x-1)(5x+4)=0
10.x²-x-2-70=0
(x-9)(x+8)=0
11.x²+2x+1+2x²-2x=0
3x²+1=0
3x²>=0
3x²+1>0
无解
12.把x+1看成个整体
[(x+1)-1][(x+1)-2]=0
x(x-1)=0
13.利用x²-y²=(x+y)(x-y)
(x-2)²-(2x+3)²=0
[(x-2)+(2x+3)][(x-2)-(2x+3)]=0
(3x+1)(-x-5)=0
(3x+1)(x+5)=0
14.(2x+3)²-4(2x+3)=0
(2x+3)(2x+3-4)=0
(2x+3)(2x-1)=0
15.2x²-12x+18-x²+9=0
x²-12+27=0
(x-3)(x-9)=0
能分解因式的都分解了,过程全在这里了
结果就不用写了吧

回答3:

1.36y²-25-24=0
(6y-7)(6y+7)=0
2.(x-3)[4(x-3)-x]=0
(x-3)(4x-12-x)=0
3(x-3)(x-4)=0
3.x²+8x+16-2x+1=0
x²+6x+17=0
△=6²-17*4*1<0,无法分解,故为无解
4.(2t+3)[(2t+3)-3]=0
2t(2t+3)=0
5.2y²-6y+9-9=0
2y(y-3)=0
6.x²+√2x²-x+√2x=0
(x+√2x-1+√2)x=0
7.x²-x-56=0
(x-8)(x+7)=0
8.x-2-x(x-2) =0
(x-2)(1-x)=0
(x-2)(x-1)=0
9.x(5x+4)-5x+4 =0
(x-1)(5x+4)=0
10.x²-x-2-70=0
(x-9)(x+8)=0
11.x²+2x+1+2x²-2x=0
3x²+1=0
3x²>=0
3x²+1>0
无解
12.把x+1看成个整体
[(x+1)-1][(x+1)-2]=0
x(x-1)=0
13.利用x²-y²=(x+y)(x-y)
(x-2)²-(2x+3)²=0
[(x-2)+(2x+3)][(x-2)-(2x+3)]=0
(3x+1)(-x-5)=0
(3x+1)(x+5)=0
14.(2x+3)²-4(2x+3)=0
(2x+3)(2x+3-4)=0
(2x+3)(2x-1)=0
15.2x²-12x+18-x²+9=0
x²-12+27=0
(x-3)(x-9)=0

回答4:

①(6y+5)(6y-5)-24=0
36y²+30y-30y-25-24=0
36y²-49=0
(6y-7)(6y+7)=0
y=7/6或y=-7/6
②4(x-3)²-x(x-3)=0
(x-3)(4x-12-x)=0
(x-3)(3x-12)=0
(x-3)(x-4)=0
x=3或x=4
③(x+4)²-(2x-1)=0
x²+8x+16-2x+1=0
x²+6x+17=0
△=6²-17×4×1<0,无法分解
故无解
④(2t+3)²=3(2t+3)
(2t+3)[(2t+3)-3]=0
2t(2t+3)=0
t=0或t=-3/2
⑤(3-y)²+y²=9
2y²-6y+9-9=0
2y(y-3)=0
y=0或y=3
⑥(1+√2)x²-(1-√2)x=0
x²+√2x²-x+√2x=0
(x+√2x-1+√2)x=0
x=0或x=1-2√2
⑦x²=x+56
x²-x-56=0
(x-8)(x+7)=0
x=8或x=-7
⑧x-2=x(x-2)
x-2-x(x-2)=0
(x-2)(1-x)=0
(x-2)(x-1)=0
x=2或x=1
⑨x(5x+4)=5x+4
x(5x+4)-5x+4=0
(x-1)(5x+4)=0
x=1或x=-4/5
⑩(x-1)(x+2)=70
x²-x-2-70=0
(x-9)(x+8)=0
x=9或x=-8
⑴(x+1)²+2x(x-1)=0
x²+2x+1+2x²-2x=0
3x²+1=0
因为3x²>=0
所以3x²+1>0
故无解

⑵(x+1)²-3(x+1)+2=0
[(x+1)-1][(x+1)-2]=0
x(x-1)=0
x=0或x=1
⑶(x-2)²=(2x+3)²
(x-2)²-(2x+3)²=0
[(x-2)+(2x+3)][(x-2)-(2x+3)]=0
(3x+1)(-x-5)=0
(3x+1)(x+5)=0
x=-1/3或x=-5
⑷(2x+3)²=4(2x+3)
(2x+3)²-4(2x+3)=0
(2x+3)(2x+3-4)=0
(2x+3)(2x-1)=0
x=1/2或x=-3/2
⑸2(x-3)²=x²-9
2x²-12x+18-x²+9=0
x²-12+27=0
(x-3)(x-9)=0
x=3或x=9