Đáp án:
Giải thích các bước giải:
a,(3x-2)(4x+3)=(2-3x)(x-1)
<=>(3x-2)(4x+3)+(3x-2)(x-1)=0
<=>(3x-2)(4x+3+x-1)=0
<=>3x-2=0
5x+2=0
<=>3x=2
5x=-2
<=>x=2/3
x=-0,4
b,x^2+(x+3)(5x-7)=9
<=>x^2+5x^2+8x-21=9
<=>6x^2+8x=30
<=>6x^2+8x-30=0
<=>(6x-10)(x+3)=0
<=>6x-10=0
x+3=0
<=>6x=10
x=-3
<=>x=5/3
x=-3
d,2x^2+5x+3=0
<=>(x+1)(2x+3)=0
<=>x+1=0
2x+3=0
<=>x=-1
2x=-3
<=>x=-1
x=-1,5
d,x+1/2+x+1/3=x+1/4+x+1/5
<=>(x+1)30+(x+1)20=(x+1)15+(x+1)20
<=>30x+30+20x+20=15x+15+12x+12
<=>50x-27=27-50
<=>23x=-23
<=>x=-1