Приведите дроби (a-2b)/(b^2-a^2) и (5b)/(4a-4b) к общему знаменателю.

[latex] frac{a-2b}{(b-a)(b+a)}= frac{4(a-2b)}{4(b-a)(b+a)} \ \ frac{5b}{4(a-b)} = -frac{5b}{4(b-a)} =- frac{5b*(b+a)}{4(b-a)(b+a)} [/latex]

[latex] frac{a-2b}{b ^{2} -a ^{2} }= frac{a-2b}{(b-a)(b+a)} = frac{4(a-2b)}{4(b-a)(b+a)} = frac{4a-8b}{4b ^{2} -a ^{2} } \ \ frac{5a}{4a-4b} =- frac{5a}{4(b-a)} =- frac{5a(b-a)}{4(b-a)(b+a)} =- frac{5ab-5a ^{2} }{4b ^{2} -a ^{2} } [/latex]