Question

Tính

a) 2^2. 5^2 -64 :2^3

b) 3^5. 9 :243

c) 4.2^5.2^3.\(\dfrac{1}{16}\)

d) \(\dfrac{11.3^{22}.3^7-9^{15}}{3^{28}}\)

Answer 1

a) \(2^2\cdot5^2-64:2^3\)

\(=4\cdot25-2^6:2^3\)

\(=100-2^3=100-8\)

\(=92\)

b) \(3^5\cdot9:243\)

\(=3^5\cdot9:3^5=9\)

c) \(4\cdot2^5\cdot2^3\cdot\dfrac{1}{16}\)

\(=2^{10}\cdot\dfrac{1}{2^4}=2^6\)

\(=64\)

d) \(\dfrac{11\cdot3^{22}\cdot3^7-9^{15}}{3^{28}}\)

\(=\dfrac{11\cdot3^{29}-\left(3^2\right)^{15}}{3^{28}}\)

\(=\dfrac{11\cdot3^{29}-3^{30}}{3^{28}}=\dfrac{3^{29}\left(11-3\right)}{3^{28}}\)

\(=\dfrac{3^{29}\cdot8}{3^{28}}=3\cdot8=24\)