`a)(3x+2)²-(3x+5)(3x+1)=5`
`⇔9x²+12x+4-(9x²+3x+15x+5)=5`
`⇔9x²+12x+4-9x²-3x-15x-5=5`
`⇔-6x-1=5`
`⇔-6x=5+1`
`⇔-6x=6`
`⇔x=6:(-6)`
`⇔x=-1`
Vậy `x=-1`
`b)(2x-3)(3x+1)-(2x-1)²=2x(x-5)+9`
`⇔6x²+2x-9x-3-(4x²-4x+1)=2x²-10x+9`
`⇔6x²+2x-9x-3-4x²+4x-1=2x²-10x+9`
`⇔2x²-3x-4=2x²-10x+9`
`⇔2x²-3x-2x²+10x=9+4`
`⇔7x=13`
`⇔x=13/7`
Vậy `x=13/7`
`c)4(x+1)²+(2x-1)²-8(x-1)(x+1)=11`
`⇔4(x²+2x+1)+4x²-4x+1-8(x²-1)=11`
`⇔4x²+8x+4+4x²-4x+1-8x²+8=11`
`⇔4x+13=11`
`⇔4x=11-13`
`⇔4x=-2`
`⇔x=-2/4`
`⇔x=-1/2`
Vậy `x=-1/2`
`d)(2x+3)²+2(x-2)²=6(x-5)(x-7)`
`⇔4x²+12x+9+2(x²-4x+4)=(6x-30)(x-7)`
`⇔4x²+12x+9+2x²-8x+8=6x²-42x-30x+210`
`⇔6x²+4x+17=6x²-72x+210`
`⇔6x²+4x-6x²+72x=210-17`
`⇔76x=193`
`⇔x=193/76`
Vậy `x=193/76`
`e)(x+7)²+2(x-3)(x+2)=3(x-1)²`
`⇔x²+14x+49+(2x-6)(x+2)=3(x²-2x+1)`
`⇔x²+14x+49+2x²+4x-6x-12=3x²-6x+3`
`⇔3x²+12x+37=3x²-6x+3`
`⇔3x²+12x-3x²+6x=3-37`
`⇔18x=-34`
`⇔x=-34/18`
`⇔x=-17/9`
Vậy `x=-17/9`
`f)3(x-5)(x+5)+2(x+4)²=5(x-6)²`
`⇔3(x²-25)+2(x²+8x+16)=5(x²-12x+36)`
`⇔3x²-75+2x²+16x+32=5x²-60x+180`
`⇔5x²+16x-43=5x²-60x+180`
`⇔5x²+16x-5x²+60x=180+43`
`⇔76x=223`
`⇔x=223/76`
Vậy `x=223/76`
`g)3(3x+2)²-2(3x+2)(3x-2)=(3x-1)²`
`⇔3(9x²+12x+4)-2(9x²-4)=9x²-6x+1`
`⇔27x²+36x+12-18x²+8=9x²-6x+1`
`⇔9x²+36x+20=9x²-6x+1`
`⇔9x²+36x-9x²+6x=1-20`
`⇔42x=-19`
`⇔x=-19/42`
Vậy `x=-19/42`
