РОЗДІЛ 2. Раціональні вирази - Вправи 50 - 200 » 189

189. Спростіть вираз: 1) 2/〖9a〗^2 • 18 = 2/〖9a〗^2 • 18/1 = (2 •18)/(〖9a〗^2 •1) = 4/a^2 ; 2) 2/7b • 28b2 = 2/7b • 〖28b〗^2/1 = (2 • 〖28b〗^2)/(7b •1) = 8b; 3) 2/15x • (–24x3) = 2/15x • (–〖24x〗^3/1) = –(2 • 〖24x〗^3)/(15x •1) = –〖16x〗^2/5; 4) (a + 2) • 9/(2+a) = (a+2)/1 • 9/(2+a) = ((a+2)•9)/(1 •(2+a)) = 9; 5) (3b – 12) • 4/(4-b) = (3b-12)/1 • 4/(4-b) = ((3b-12)•4)/(1 •(4-b) ) = (3(b-4)•4)/(4-b) = –(3(b-4)•4)/(b-4) = –12; 6) (a – 4a2) • (–5/(4a-1)) = 〖a-4a〗^2/1 • (–5/(4a-1)) = –(〖(a-4a〗^2) •5)/(1 •(4a-1)) = –(a(1-4a)•5)/(4a-1) = (a •(a-1)•5)/(4a-1) = 5a