Question

帮我解答一元二次方程（要过程）谢谢啦！

1. (x－1)－(x+4)＝1
2. x²－5x+2＝－x²
3. 3x²－5＝－2x²+x－4
4 . x(4x+2)＝0
5. 3x²－5x ＝0
6. (x－2)3x＝4
7. －x²－x－1＝0
8. (x－2)x3＝4

Answer 1

1. (x－1)－(x+4)＝1 x-1-x-4=1 -5=1 题目错！
2. x²－5x+2＝－x² 2x²－5x+2＝0 （2x-1)(x-2)=0 x1=1/2 x2=2
3. 3x²－5＝－2x²+x－4 3x²－5+2x²-x+4=0 5x²-x-1=0 x1=(1+(1+4*5*1)^0.5)/(2*5)=(1+(21)^0.5)/10 x2=(1-(1+4*5*1)^0.5)/(2*5)=(1-(21)^0.5)/10
4 . x(4x+2)＝0
x1=0 x2=-1/25. 3x²－5x ＝0 x(3x－5)＝0 x1=0 x2=5/3
6. (x－2)3x＝4 3x²-6x=4 3x²-6x-4=0 x1=(6+(6^2+4*3*4)^0.5)/(2*3)=(6+(48)^0.5)/6=(3+(12)^0.5)/3 x2=(6-(6^2+4*3*4)^0.5)/(2*3)=(6-(48)^0.5)/6=(3-(12)^0.5)/3
7. －x²－x－1＝0 x²+x+1＝0 x1=-1/2+((1/2)^2-1)^0.5=-1/2+((1/4)-1)^0.5=-1/2+(-3/4)^0.5=-1/2+(-3)^0.5/2 x2=-1/2-((1/2)^2-1)^0.5=-1/2-((1/4)-1)^0.5=-1/2-(-3/4)^0.5=-1/2-(-3)^0.5/2
8. (x－2)*3＝4 x-2=4/3 x=4/3+2=10/3

Answer 2

1. (x－1)－(x+4)＝1 ??????????一元二次方程

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

3. 3x²－5＝－2x²+x－4
5x²-x-1=0
x1,2=(1±√21)/10

4 . x(4x+2)＝0
x1=0,x2=-1/2

5. 3x²－5x ＝0
x(x-5/3)=0
x1=0,x2=5/3

6. (x－2)3x＝4
3x²-6x-4=0
(x-1)²=7/3
x1,2=1±√(7/3)

7. －x²－x－1＝0
x²+x+1＝0
△=1-4=-3<0,
8. (x－2)x3＝4
(6)