Đáp án:
Giải thích các bước giải:
1) (x+2y)²=x²+4xy+4y²
2) (2x+3y)²=4x²+12xy+9y²
3) (3x-2y)²=9x²-12xy+4y²
4) (5x-y)²=25x²-10xy+y²
5) (x+$\frac{1}{4}$)²=x²+$\frac{1}{2}$x+ $\frac{1}{16}$
6) (2x-$\frac{1}{2}$)²=4x²+x+ $\frac{1}{4}$
7) ($\frac{1}{3}$x-$\frac{1}{2}$y)²= $\frac{1}{9}$x²+ $\frac{1}{3}$xy+$\frac{1}{4}$ y²
8) (3x+1)(3x-1)=9x²-1
9) (x²+$\frac{2}{5}$y)(x²- $\frac{2}{5}$y)=$x^{4}$+$\frac{4}{25}$y²
10) ($\frac{x}{2}$-y)($\frac{x}{2}$+y)=$\frac{x^{2}}{4}$-y²
11) ($\frac{x}{2}$-2y)²=$\frac{x^{2}}{4}$-2xy+4y²
12) (√2x-y)²=2x-2√2xy+y²
13) ($\frac{3x}{2}$+3y)²=$\frac{9x^{2}}{4}$+9xy+9y²
14) (√2x+√8y)²=2x²+8xy+8y²
16) ($\frac{1}{2}$x-4y)²=$\frac{1}{4}$x²-4xy+16y²
17) ($\frac{x}{2}$+2y²)($\frac{x}{2}$-2y²)=$\frac{x^{2}}{4}$-$4y^{4}$
18) (x²-4)(x²+4)=$x^{4}$-16
19) (x+y)²+(x-y)²=x²+2xy+y²+x²-2xy+y²=2x²+2y²
20) (2x+3)² - (x+1)²=4x²+12x+9-x²-2x-1=3x²+10x+8
15) (x+$\frac{1}{6}$y+3)=x²+$\frac{1}{36}$y²+9+$\frac{1}{3}$xy+y+6x
Cho mk ctlhn nha
Chúc bạn học tốt ^-^
