Question

[Olivia]

Bài 2: Thực hiện phép tính (tính hợp lí nếu có)

a) \(\left(-2\right)^3+\frac{1}{2}\div\frac{1}{8}-\sqrt{25}+\left|-64\right|\)

b) \(\left(\frac{-3}{4}+\frac{2}{7}\right):\frac{2}{3}+\left(\frac{-1}{4}+\frac{5}{7}\right):\frac{2}{3}\)

c)\(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)

Giúp mk với!!! Mk cần gấp lắm!!!

Answer 1

[Nguyễn Lê Phước Thịnh]

a) Ta có: \(\left(-2\right)^3+\frac{1}{2}:\frac{1}{8}-\sqrt{25}+\left|-64\right|\)

\(=-8+\frac{1}{2}\cdot8-5+64\)

\(=-8+4-5+64=55\)

b) Ta có: \(\left(\frac{-3}{4}+\frac{2}{7}\right):\frac{2}{3}+\left(\frac{-1}{4}+\frac{5}{7}\right):\frac{2}{3}\)

\(=\left(\frac{-3}{4}+\frac{2}{7}\right)\cdot\frac{3}{2}+\left(\frac{-1}{4}+\frac{5}{7}\right)\cdot\frac{3}{2}\)

\(=\left(\frac{-3}{4}+\frac{2}{7}+\frac{-1}{4}+\frac{5}{7}\right)\cdot\frac{3}{2}\)

\(=0\cdot\frac{3}{2}=0\)

c) Ta có: \(\frac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)

\(=\frac{2^{10}\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot20}=\frac{2\left(2^9\cdot9^4-6^9\right)}{6^8\left(2^2+20\right)}=\frac{-1}{3}\)

Answer 2

[thái quang phong]

a) ( -2 )³ + \(\frac{1}{2}:\frac{1}{8}\) - √25 + \(|-64|\)

= \(\frac{-8}{1}\) + \(\frac{1}{2}.\frac{8}{1}\) - \(\frac{5}{1}\) + \(\frac{64}{1}\)

= \(\frac{-16}{2}+\frac{1}{2}.\frac{8}{1}-\frac{10}{2}+\frac{128}{2}\)

= \(\frac{-16}{2}+\frac{8}{2}-\frac{10}{2}+\frac{128}{2}\)

= \(\frac{-16+8-10+128}{2}\) = \(\frac{110}{2}\) = 55