X⁵ - x² + x² - 1 = (x⁵ - x²) + (x² - 1) = x²(x³ - 1) + ( x - 1)(x+ 1) =
= x²( x - 1)(x² + x + 1) + ( x - 1)( x + 1) = ( x - 1)(x²(x²+x+1) + x + 1) =
= ( x - 1)( x⁴ + x³ + x² + x + 1)
У=12-5(2x-1)-3(5-4x)
y=12-10x+5-15+12x
y=2+2x
√а-1/√а+1+√а+1/√а-1
(√а-1)²+(√а+1)²/а-1=а-2√а+1+а+2√а+1/а-1=2(а+1)/а-1