Вправи 101 - 200 » 166 (6-8)

6) 7x/(x+2) – (x-8)/(3x +6) • 84/(x^2- 8x) = 7x/(x+2) – ((x-8) • 84)/(3(x+2)x(x-8)) = –28/(x(x+2)) = –28/(x^2+ 25x); 7) (a\a+3 – (9a-9)/(a+3)) : (a^2- 3a)/(a+3) = (a(a+3)- (9a-9))/(a+3) • (a+3)/(a(a-3)) = (a^2+ 3a-9a+9)/(a+3) • (a+3)/(a(a-3)) = (a^2- 6a+9)/(a+3) • (a+3)/(a(a-3))= ((a-3)^2 (a+3))/((a+3) • a(a-3)) = (a-3)/a; 8) (a^(\a+8)/(a+2) – 8^(\a+2)/(a+8)) • (a^2+ 8a)/(a-4) = (a(a+8)- 8(a+2))/((a+2)(a+8)) • (a(a+8))/(a-4) = (a^2+ 8a-8a-16)/((a+2)(a+8)) • (a(a+8))/(a-4) = ((a^2- 16) • a • (a+8))/((a+2)(a+8)(a-4)) = ((a-4)(a+4)(a+8))/((a+2)(a+8)(a-4)) = (a(a+4))/(a+2) = (a^2+ 4a)/(a+2).