Question

Se A = -5³ -6² / -7² e B = ( -5)³ + ( -6)²/ (-7)² então A - B = K/49 , onde K é igual a : a) 250 b) 72 c) -72 d) zero e) 178

Answer 1

$A=-5^3-6^2/-7^2=-5^3- \frac{6^2}{-7^2}=-125+ \frac{36}{49} \\ \\B=(-5)^3+(-6)^2/(-7)^2=(-5)^3+\frac{(-6)^2}{(-7)^2}=-125+ \frac{36}{49} \\ \\ \\A-B= \frac{k}{49} \\ \\(-125+ \frac{36}{49})-(-125+ \frac{36}{49})= \frac{k}{49} \\ \\-125+ \frac{36}{49}+125- \frac{36}{49}= \frac{k}{49} \\ \\0= \frac{k}{49} \\ \\ \frac{k}{49} =0\\ \\ k =49\cdot 0\\ \\k=0$