Đáp án:
Giải thích các bước giải:
$\text{a) 2(x-3)²+(3x-2)²-11(x+4)(x-4)=20}$
$\text{⇔2(x²-6x+9)+9x²-12x+4-11(x²-16)=20}$
$\text{⇔2x²-12x+18+9x²-12x+4-11x²+176-20=0}$
$\text{⇔-24x+178}$
$\text{⇔-24x=-178}$
$\text{⇔ x= $\frac{178}{24}$ = $\frac{89}{12}$ }$
$\text{Vậy ....}$
$\text{b) (2x+y)(4x²-2xy+y²)-(2x-y)(4x²+2xy+y²)=16}$
$\text{⇔ 8x³+y³-8x³+y³=16}$
$\text{⇔2y³=16}$
$\text{⇔y³=8}$
$\text{⇔y³=2³}$
$\text{⇔y=2}$
$\text{Vậy ....}$