a.(-5)^8.(-5)^3=(-5)^11
b.(3/8)^7:(3/8)^4=(3/8)^3
\(a)\left(-5\right)^8.\left(-5\right)^3=\left(-5\right)^{8+3}=\left(-5\right)^{11}\)
\(b)\left(\dfrac{3}{8}\right)^7:\left(\dfrac{3}{8}\right)^4=\left(\dfrac{3}{8}\right)^{7-4}=\left(\dfrac{3}{8}\right)^3\)
Chúc bạn học tốt!
(-5)^8 . (-5)^3 = (-5)^8+3=(-5)^11
(3/8)^7:(3/8)^4 = (3/8)^7-4 = (3/8)^3