Вправа 201 - 300 » 245

245. Перемножте дроби. a) (a+3)/〖10a〗^2 • (6-2a)/a • 〖5a〗^3/(3- a) = ((a+3)•(-2)(a-3)• 〖5a〗^3)/(〖10a〗^2• a•(-1)(a-3)) = a + 3; б) 0,2/x • (x^2-1)/2x • 5x/(x+1) = (0,2•5• x(x-1)(x+1))/(x•2x•(x+1)) = (x-1)/2x; в) 〖-6x〗^4/(〖36y〗^6 z^3 ) • (〖5y〗^4 z^7)/〖42x〗^6 • (–(〖49x〗^3 y^2)/z^4 ) = (-6•5•(-49)x^7 y^6 z^7)/(35•42y^6 z^7 x^6 ) = x; г) (a^3 b^2)/〖-20c〗^4 • (〖-5a〗^4 c)/〖24b〗^5 • (〖16b〗^3 c^3)/〖-30a〗^6 = (-5• 〖16a〗^7 b^5 c^4)/(-20•24•(-30)c^4 b^5 a^6 ) = –2a/(24•15) = (-a)/(12•15) = –a/180.