Question

просьба все расписать​

Answer 1

$\dfrac{(a+2b)^{2}-(a-2b)^{2}}{4a} =\dfrac{(a+2b-a+2b)(a+2b+a-2b)}{4a}=\\\\=\dfrac{4b\cdot2a}{4a} =\boxed{2b}$

Answer 2

$\boxed{ {a}^{2} - {b}^{2} = (a + b)(a - b) }$

$\frac{ {(a + 2b)}^{2} - {(a - 2b)}^{2} }{4a} = \frac{ \big((a + 2b) + (a - 2b) \big) \big((a + 2b) - (a - 2b) \big)}{4a} = \frac{(a \cancel{+2b} + a \cancel{- 2b})( \cancel{a} + 2b \cancel{- a} + 2b)}{4a} = \frac{2a \times 4b}{4a} = \frac{8ab}{4a} = \boldsymbol{2b}$