Question

Найдите значение выражения:
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Answer 1

$3a- frac{b+15a^2}{5a-2}+ frac{5a}{2-5a}= frac{3a(5a-2)}{5a-2} - frac{b+15a^2}{5a-2}- frac{5a}{5a-2}= \ =frac{15a^2-6a-b-15a-5a}{5a-2} = frac{-11a-b}{5a-2}= frac{-11*(-0,8)-16}{5(-0,8)-2}= frac{-7,2}{-4-2}= frac{7,2}{6}=1,2$

$frac{m-6n^2}{2n-1}+3n- frac{2n}{1-2n}= frac{m-6n^2}{2n-1}+ frac{3n(2n-1)}{2n-1} + frac{2n}{2n-1}= \ =frac{m-6n^2+ 6n^2-3n + 2n}{2n-1} = frac{m-n}{2n-1}=frac{12-(-3)}{2(-3)-1}=frac{15)}{-7}=-2 frac{1}{7}$

$frac{3x-10y^2}{2y-3} +5y+ frac{2x-13y}{3-2y}=frac{3x-10y^2}{2y-3} + frac{5y(2y-3)}{2y-3} - frac{2x-13y}{2y-3} = \ =frac{3x-10y^2 + 10y^2-15y - 2x+13y}{2y-3}=frac{x-2y}{2y-3}=frac{14-2(-3,5)}{2(-3,5)-3}=frac{14+7}{-7-3}=-2,1$

$frac{m^2-n}{m-7} -m- frac{6m}{7-m}= frac{m^2-n}{m-7} - frac{m(m-7)}{(m-7)} + frac{6m}{m-7}=frac{m^2-n - m^2+7m + 6m}{m-7} = \ =frac{-n +13m}{m-7}=frac{-(-4) +13*2}{2-7}= frac{4 +26}{-5}=- frac{30}{5}=-6$