Đáp án:
$\text{Bài 1:}$
`a)x=35/6`
`b)x=-2`
$\text{Bài 2:}$
`a)9x^2-49x+29`
`b)6x^2+13x-12`
Giải thích các bước giải:
$\text{Bài 1:}$
`a)(2x-5)(2x+5)-(2x-3)^2-36=0`
`⇔4x^2-25-(4x^2-12x+9)-36=0`
`⇔4x^2-25-4x^2+12x-9-36=0`
`⇔12x-70=0`
`⇔12x=70`
`⇔x=35/6`
`b)x(2+x)(2-x)+x(x+3)^2=6x^2-26`
`⇔x(4-x^2)+x(x^2+6x+9)=6x^2-26`
`⇔4x-x^3+x^3+6x^2+9x-6x^2+26=0`
`⇔13x+26=0`
`⇔13x=-26`
`⇔x=-2`
$\text{Bài 2:}$
`a)x(x-4)(x+4)-(x-3)^3-6x+2`
`=x(x^2-16)-(x^3-9x^2+27x-27)-6x+2`
`=x^3-16x-x^3+9x^2-27x+27-6x+2`
`=9x^2-49x+29`
`b)x(3+2x)(3-2x)+4x(x+1)^2-2x^2-12`
`=x(9-4x^2)+4x(x^2+2x+1)-2x^2`-12`
`=9x-4x^3+4x^3+8x^2+4x-2x^2-12`
`=6x^2+13x-12`