`1)`
`(x+8)(x+6)-x^2=104`
`\to x^2+14x+48-x^2=104`
`\to (x^2-x^2)+14x+48=104`
`\to 14x=104-48`
`\to 14x=56`
`\to x=4`
Vậy `x=4`
`2)`
`(x+1)(x+2)-(x-3)(x+4)=6`
`\to (x^2+3x+2)-(x^2+x-12)=6`
`\to x^2+3x+2-x^2-x+12=6`
`\to (x^2-x^2)+(3x-x)+(2+12)=6`
`\to 2x+14=6`
`\to 2x=-8`
`\to x=-4`
Vậy `x=-4`
`3)`
`3(2x-1)(3x-1)-(2x-3)(9x-1)-3=-3`
`\to 3(6x^2-5x+1)-(18x^2-29x+3)-3+3=0`
`\to 18x^2-15x+3-18x^2+29x-3-3+3=0`
`\to (18x^2-18x^2)+(29x-15x)+(3-3-3+3)=0`
`\to 14x=0`
`\to x=0`
Vậy `x=0`
`4)`
`2(3x-1)(2x+5)-6(2x-1)(x+2)=1`
`\to 2(6x^2+13x-5)-6(2x^2+3x-2)=1`
`\to 12x^2+26x-10-12x^2-18x+12=1`
`\to (12x^2-12x^2)+(26x-18x)+(12-10)=1`
`\to 8x+2=1`
`\to 8x=-1`
`\to x=-1/8`
Vậy `x=-1/8`
`5)`
`(3x-1)(2x+7)-(x+1)(6x-5)=(x-2)-(x-5)`
`\to (6x^2+19x-7)-(6x^2+x-5)=x-2-x+5`
`\to 6x^2+19x-7-6x^2-x+5=3`
`\to (6x^2-6x^2)+(19x-x)+(5-7)=3`
`\to 18x-2=3`
`\to 18x=5`
`\to x=5/18`
Vậy `x=5/18`
