(х² - ху) / (х²у-ху²) = х(х -у) / ху(х-у) = 1/у
(с² - 6с) /(36-с²) = -с(6-с) / (6-с)(6+с) = -с/(6+с) = - с/(с+6)
(у²-х²)/ (х² -2ху+у²) = (у-х)(у+х)/ (х-у)² = -(х-у)(у+х)/(х-у)² =
= - (х+у)/(х-у)
(4n² - 4n + 1)/ (2n - 4n²) = ( (2n)² - 2*2n*1 + 1²) / -2n(2n -1) =
= (2n - 1)² / -2n(2n-1) = (2n-1) / (-2n) = - (2n -1)/2n =
= (1-2n)/2n = 1/2n - 2n/2n = 1/2n - 1
(ax² - 2x² -ay² + 2y²) / (ax+ay -2x-2y) =
= (x² *(a-2) - y² *(a-2) ) / (a(x+y) -2(x+y))=
= (a-2)(x²-y²) / (a-2)(x+y) =
= (x-y)(x+y) / (x+y) = (x-y) / 1 =
= x - y
и) ???
25x² - 10x +y² = (5x)² - 2*5x + y² =5x(5x-2) + y²
ощущение того, что в условии пропущен у => - 10xy
25х² - 10ху + у² = (5х)² - 2*5х *у + у² = (5х - у)²
16х² + 24ху+9у² = (4х)² + 2*4х *3у + (3у)² =
= (4х + 3у)²
49 -х² = 7² - х² =(7-х)(7+х)
b² - 0.0001a⁴ = b² - (0.01a²)² = (b -0.01a²)(b+0.01a²)
16 - a⁴ = 4² - (a²)² = (4+a²)(4-a²) = (4+a²)(2² -a²) =
= (4+a²)(2-a)(2+a)