Question

[VALENDO 65 PONTOS]

Calcule o valor numérico das expressões algébricas

a )$\frac{5a-m}{ a^{2}-3m^{2} }$ PARA a = 4 e m = 1

b )$\frac{A+B+C}{5}$ PARA a = -3 , b = - 9 , c = -8

CÁLCULOS E RESPOSTA ^^

Answer 1

$A)~~~Para~~a=4~~e~~m=1:\\\\\\ \dfrac{5a-m}{a^2-3m^2} \to~~ \dfrac{5\times4-1}{4^2-3\times1^2} \to~~ \dfrac{20-1}{16-3\times 1} \to~~ \dfrac{19}{16-3} \to ~~\large\boxed{\dfrac{19}{13}}$




$b )~~~Para~~a=-3~;~~b=-9~~e~~c=-8\\\\\\ \dfrac{a+b+c}{5}\to~~ \dfrac{(-3)+(-9)+(-8)}{5}\to~~ \dfrac{-3-9-8}{5}\to~~ \dfrac{-20}{5}\to~~ \large\boxed{-4}$

Answer 2

$a = 4$
$m = 1$

$\frac{5a - m}{a^2-3m^2}$

$\frac{5.4-1}{4^2 - 3.1^2} = \frac{20-1}{16-3} = \frac{19}{13}$


$A = -3$

$B = -9$

$C = -8$

$\frac{A+B+C}{5}$

$\frac{-3 - 9 - 8}{5} = \frac{-20}{5} = -4$

Respostas:

a) $\frac{19}{13}$

b) $-4$