Вправи 101 - 200 » 139

139. Виконайте множення: 1) (3a+b)/4c • c/(3a+b) = 1/4; 2) (ab- b^2)/8 • 4a/b^4 = (b(a-b) • 4a)/(8b^4 ) = (a(a-b))/(2b^3 ) = (a^2- ab)/(2b^3 ); 3) (5x-5y)/x^6 • x^3/(x-y) = (5(x-y)• x^3)/(x^6 •(x-y)) = 5/x^3 ; 4) 18b/(b^2- 16) • (b+4)/3b = (18b •(b+4))/((b-4)(b+4)•3b) = 6/(b-4); 5) 6/(m^2- 9n^2 ) • (m-3n)/1 = (6 •(m-3n))/((m-3n)(m+3n)) = 6/(m+3n); 6) (3c-9)/(9c^2+ 6c+1) • (3c+1)/(c-3) = (3(c-3)(c+1))/((3c+1)^2 (c-3)) = 3/(3c+1).