Bài 1 :
a) `5^2 . 2^3 + 3^2 . 7 - 8^2.2`
`= 25 . 8 + 9 . 7 - 64 . 2`
`= 200 + 63 - 128`
`= 135`
b) `(5. 2^2 - 20) : 5 + 3^2 . 6`
`= (5 . 4 - 20) : 5 + 9 . 6`
`= 0 : 5 + 54`
`= 54`
c) `(24. 5 - 5^2 . 2) : (5. 2) - 3`
`= (120 - 25 . 2) : 10 - 3`
`= (120 - 50) : 10 - 3`
`= 70 : 10 - 3`
`= 7 - 3`
`= 4`
d) `[(5^2 . 2^3 - 7^2 . 2) : 2] . 6 - 7 . 2^5`
`= [(25 . 8 - 49 . 2) : 2] . 6 - 7 . 2^5`
`= [(200 - 98) : 2] . 6 - 7 . 32`
`= [102: 2] . 6 - 224`
`= 51 . 6 - 224`
`= 306 - 224`
`= 82`
e) `3^2 . [(5^2 − 3) : 11] - 2^4 + 2. 10^3`
`= 9 . [(25−3):11] - 16 + 2 . 100`
`= 9 . [22:11] - 16 + 2 . 100`
`= 9 . 2 - 16 + 2 . 100`
`= 18 - 16 + 200`
`= 2 + 200`
`= 202`
Bài 2:
a) `5.(x - 7) - 10 = 2^3 . 5`
`⇒ 5.(x - 7) - 10 = 8 . 5`
`⇒ 5.(x - 7) - 10 = 40`
`⇒ 5.(x - 7) = 40 + 10`
`⇒ 5.(x - 7) = 50`
`⇒ x - 7 = 50 : 5`
`⇒ x - 7 = 10`
`⇒ x = 17`
b) `5^3 - 5(4 + x) = 15`
`⇒ 125 - 5(4 + x) = 15`
`⇒ 5(4 + x) = 125 - 15`
`⇒ 5(4 + x) = 110`
`⇒ 4 + x = 110 : 5`
`⇒ 4 + x = 22`
`⇒ x = 18`
c) `7^2-7.(13-x)=14`
`⇒ 49 - 7.(13 - x) = 14`
`⇒ 7.(13 - x) = 49 - 14`
`⇒ 7.(13 - x) = 35`
`⇒ 13 - x = 35 : 7`
`⇒ 13 - x = 5`
`⇒ x = 8`
d) `3^(x+1)+3^x=36`
`⇒ 3^x . 3 + 3^x = 36`
`⇒ 3^x . (3 + 1) = 36`
`⇒ 3^x . 4 = 36`
`⇒ 3^x = 36 : 4`
`⇒ 3^x = 9`
`⇒ x = 2`
e) `64 : 2^x = 8`
`⇒ 2^x = 64 : 8`
`⇒ 2^x = 8`
`⇒ x = 3`
