a) 5x−10x2+7 : (2x - 4) =5x−10x2+7:2x−41=5x−10x2+7.12x−4
=5(x−2).1(x2+7).2(x−2)=52(x2+7)
b) (x2 -25) : 2x+103x−7 =x2−251:2x+103x−7=x2−251.3x−72x+10
=(x−5)(x+5)(3x−7)2(x+5)=(x−5)(3x−7)2
c) x2+x5x2−10x+5:3x+35x−5 = x2+x5x2−10x+5.5x−53x+3
=x(x+1).5(x−1)5(x−1)2.3(x+1)=x3(x−1)