Bài 3: 

a: Ta có: 60-3(x-2)=51

\(\Leftrightarrow x-2=3\)

hay x=5

b: Ta có: \(4x-20=25:2^2\)

\(\Leftrightarrow4x=\dfrac{25}{4}+20=\dfrac{105}{4}\)

hay \(x=\dfrac{105}{16}\)

c: Ta có: \(8\cdot6+288:\left(x-3\right)^2=50\)

\(\Leftrightarrow288:\left(x-3\right)^2=50-48=2\)

\(\Leftrightarrow\left(x-3\right)^2=144\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=12\\x-3=-12\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=15\\x=-9\end{matrix}\right.\)

a,  5 . 2 2 - 18 : 3 2

= 5.4 – 18:9

= 20 – 2 = 18

b, 17.85+15.17 – 120

= 1445+255 – 120

= 1580

c,  2 3 . 17 - 2 3 . 14

=  2 3 . ( 17 - 14 ) = 8.3 = 24

d, 20 – [30 –  5 - 1 2 ]

= 20 – (30 – 16) = 6

a: 3*5^2-16:2^2

=3*25-16:4

=75-4=71

b: =2^3(17-14)

=8*3

=24

c: =15(141+59)

=15*200

=3000

d: =17(85+15)-200

=1700-200

=1500

f: =3+2^5

=3+32

=35

g: =42(39-37):42

=39-37

=2

\(3\cdot5^2-16\cdot2^2\)

\(=3\cdot25-16:4\)

\(=75-4\)

\(=71\)

==============

\(2^3\cdot17-2^3\cdot14\)

\(=2^3\cdot\left(17-14\right)\)

\(=2^3\cdot3\)

\(=8\cdot3\)

\(=24\)

===============

\(15\cdot141+59\cdot15\)

\(=15\cdot\left(141+59\right)\)

\(=15\cdot200\)

\(=3000\)

================

\(17\cdot85+15\cdot17-120\)

\(=17\cdot\left(85+15\right)-120\)

\(=17\cdot100-120\)

\(=1700-120\)

\(=1580\)

===============

\(20-\left[30-\left(5-1\right)^2\right]\)

\(=20-\left(30-4^2\right)\)

\(=20-\left(30-16\right)\)

\(=20-14\)

\(=6\)

tui làm biến quá

a)\(3.5^2-16:2^2\)

=\(3.25-16:4\)

=\(75-4=71\)

b)\(2^3.17-2^3.14\)

=\(8.17-8.14\)

\(=8\left(17-14\right)\)

\(=8.3=24\)

c)\(15.141+59.15\)

=\(15\left(141+59\right)\)

\(=15.200\)=3000

d)17.85+15.17-120

\(=17\left(85+15\right)-120\)

=\(17.100-120\)

=\(170-120=50\)

e)\(20+[30-\left(5-1\right)^2]\)

\(=20+[30-\left(4\right)^2]\)

\(=20+\left(30-16\right)\)

\(=20+14=34\)

Bạn làm đúng ko vậy 

Chac là đúng nhỉ

1) 3.5² - 16 : 2²

= 3 . 25 - 2⁴ : 2²

= 75 - 2²

= 75 - 4

= 71

2) 2³ .17 -2³ . 14

= 2³ . ( 17 - 14 )

= 8 . 3

= 24

3) 17.85 + 15.17 - 120

= 17 . ( 85 + 17 ) - 120

= 75 . 102 - 120

= 7650 - 120

= 7530

4) 20 - [30-(5 - 1)²]

= 20 - ( 30 - 4² )

= 20 - ( 30 - 16 )

= 20 - 14

= 6

5) 3⁶ . 3² + 2³ .2²

= 3⁸ + 2⁵

= 6561 + 32

= 6593

6) 17 .85 + 15.17 - 120 + 2012⁰

= 17 . ( 85 + 15 ) - 120 + 1

= 17 . 100 - 120 + 1

= 1700 - 120 + 1

= 1580 + 1

= 1581

7) 37. 24 + 37. 76 + 63 . 79 + 21. 63

= 37 . ( 24 + 76 ) + 63 . ( 79 + 21 )

= 37 . 100 + 63 . 100

= 100 . ( 37 + 63 )

= 100 . 100

= 10000

1) \(3.5^2-16.2^2=3.25-16.4=75-64=11\)

2) \(2^3.17-2^3.14=2^3.\left(17-14\right)=8.3=24\)

3) \(17.85+15.17-120=17.\left(85+15\right)-120\)

                                               \(=17.100-120=1700-120=1580\)

4)\(20-\left[30-\left(5-1\right)^2\right]=20-\left[30-4^2\right]\)

                                                 \(=20-\left[30-16\right]=20-14=6\)

5) \(3^6.3^2+2^3.2^2=3^8+2^5=6561+32=6593\)

6) \(17.85+15.17-120+2012^0=17.\left(85+15\right)-120+1\)                 

                                                                 \(=17.100-119=1700-119=1581\)          

7) \(37.24+37.76+63.79+21.63\)  \(=37.\left(24+76\right)+63.\left(79+21\right)\)

                                                                          \(=37.100+63.100=100.\left(37+63\right)=100.100=10000\)

Sửa lại câu 1 : 

\(3.5^2-16:2^2=3.25-16:4\)

                          \(=75-4=71\)

a, 3-5²-16:2²=3-25-4=-26

b,2³.17-2³.14=8(17-14)=8.3=24

c,17.85+15.17-120=17.100-120=1580

d,20-(30-(5-1)²)=20-(30-16)=20-14=6

a) 3-25-16:4

=3-25-4

=-(25+4-3)

=-26

b) 2^3.(17-14)

=2^3.3

=8.3

=24

c) 17.85+15.17-120

=17.(85+15)-120

=17.100-120

=1700-120

=1580

d)20-(30-(5-1)^2)

=20-(30-4^2)

=20-(30-16)

=20-30+16

=20+16-30

=6

a )  \(=3-25-16\div4\)

       \(=-22-4\)

        \(=-26\)

 b)   \(=2^3.\left(17-14\right)\)

         \(=27.3\)

          \(=81\)

c)  \(=17.\left(85+15-120\right)\)

      \(=17.\left(-20\right)\)

        \(=-340\)

d)     \(=20-\left(30-16\right)\)

         \(=20-14\)

          \(=6\)