`10)`
`2x(x+3)-(x-5)(2x+7)=44`
`\to (2x^2+6x)-(2x^2-3x-35)=44`
`\to 2x^2+6x-2x^2+3x+35=44`
`\to (2x^2-2x^2)+(3x+6x)+35=44`
`\to 9x+35=44`
`\to 9x=9`
`\to x=1`
Vậy `x=1`
`11)`
`(x^2-3x)(2x-1)-x(2x^2-7x)=12`
`\to (2x^3-7x^2+3x)-(2x^3-7x^2)=12`
`\to 2x^3-7x^2+3x-2x^3+7x^2=12`
`\to (2x^3-2x^3)+(7x^2-7x^2)+3x=12`
`\to 3x=12`
`\to x=4`
Vậy `x=4`
`12)`
`(x+2)(x^2-4x+1)-(x^3-2x^2+2)=-21`
`\to (x^3-2x^2-7x+2)-x^3+2x^2-2=-21`
`\to x^3-2x^2-7x+2-x^3+2x^2-2=-21`
`\to (x^3-x^3)+(2x^2-2x^2)-7x+(2-2)=-21`
`\to -7x=-21`
`\to x=3`
Vậy `x=3`
`13)`
`(x^2-1)(x+2)-x^2(x+2)=21`
`\to (x+2)(x^2-1-x^2)=21`
`\to -1(x+2)=21`
`\to -x-2=21`
`\to -x=23`
`\to x=-23`
Vậy `x=-23`
`14)`
`(x-3x^2)(x+6)+x(3x^2+x)=24-16x^2`
`\to (-3x^3-17x^2+6x)+(3x^3+x^2)=24-16x^2`
`\to -3x^3-17x^2+6x+3x^3+x^2=24-16x^2`
`\to (-3x^3+3x^3)+(x^2-17x^2)+6x=24-16x^2`
`\to -16x^2+6x=24-16x^2`
`\to -16x^2+16x^2+6x=24`
`\to 6x=24`
`\to x=4`
Vậy `x=4`
`15)`
`x(x+5)(x-5)-(x+2)(x^2-2x+4)=0`
`\to x(x^2-25)-(x^3+2^3)=0`
`\to x^3-25x-x^3-8=0`
`\to (x^3-x^3)-25x-8=0`
`\to -25x=8`
`\to x=-8/25`
Vậy `x=-8/25`
