Question

28/4a-a^2-7/a при а=-3

Answer 1

$frac{28}{4a} - a^{2} - frac{7}{a} ; a=-3 \ frac{28}{4a} - frac{4a*a^{2}}{4a} - frac{4*7}{4*a} ; a=-3 \ frac{28-4a^{3}-28}{4a} ; a=-3 \ frac{-4a^{3}}{4a} ; a=-3 \ -a^{2} ; a=-3 \ -(-3)^{2} = - 9$