Question

Очень надо решить на оценку!!!​

Answer 1

$4x^{2} -20x+25=(2x)^{2} -2*(2x)*5+5^{2} =(2x-5)^{2} =(2*12,5-5)^{2} =(25-5)^{2} =20^{2} =400$

$x^{4} -8*x^{2} y^{2} +16y^{4}=(x^{2} )^{2}  -2*x^{2} *4*(y)^{2} +4^{2} (y^{2} )^{2} =(x^{2} )^{2}  -2*x^{2} *(2y)^{2} + (4y^{2} )^{2} =(x^{2}-(2y)^{2}  )^{2}$