Срочноооо!!! Прошу!!! 2 и 3 задание

$y^2+10y+25= y^2+2y\cdot \:5+5^2= \left(y+5\right)^2$

$16x^2-8xy+y^2 = \left(4x\right)^2-2\cdot \:4xy+y^2 =\left(4x-y\right)^2$

$x^2+4x+4 =x^2+2x\cdot \:2+2^2 =\left(x+2\right)^2$

$25x^2-10xy+y^2=\left(5x\right)^2-2\cdot \:5xy+y^2 =\left(5x-y\right)^2$

$\left(5x+2\right)^2-20x = 25x^2+20x+4-20x = 25x^2+4$

$\left(10a-b\right)\left(10a+b\right)=\left(10a\right)^2-b^2=100a^2-b^2$

$\left(7x-2\right)^2+28x=49x^2-28x+4+28x=49x^2+4$

$\left(4a-b\right)\left(4a+b\right) =\left(4a\right)^2-b^2 =16a^2-b^2$