Đáp án:
Giải thích các bước giải:
a) (x + 2y)² = x² + 4xy + y²
b) (x - 3y)(x + 3y) = x² - 9y²
c) ( 5 - x )² = 25 - 10x + x²
d) ( x - 1 )² = x² - 2x + 1
e) ( 3 - y )² = 9 - 6y + y²
f) ( x - $\frac{1}{2}$ )² = x² - x + $\frac{1}{4}$
Bài 2
a) (5x + 2y)² = 25x² + 20xy + 4y²
b) (-3x + 2)² = 9x² - 12x + 4
c) ( $\frac{2}{3}$.x + $\frac{1}{3}$y)² = $\frac{4x²}{9}$ + $\frac{4}{9}$xy + $\frac{y²}{9}$
d) (2x - $\frac{5}{2}$y)² = 4x² - 10xy + $\frac{25y²}{4}$
e) (x + $\frac{4}{3}$y²)² = x² + 2.$\frac{8xy²}{3}$ + $\frac{16y^{4} }{9}$
= x² + $\frac{16xy²}{3}$ + $\frac{16y^{4} }{9}$
f) (2x² +$\frac{5}{3}$y)² = 4$x^{4}$ + 2.2.$\frac{5}{3}$x²y + $\frac{25y²}{9}$
= 4$x^{4}$ + $\frac{20}{3}$x²y + $\frac{25y²}{9}$
