Question

7.(x-9) bằng35

câu 2:2^x bằng 2^2.2

câu 3:2.3^x-1 bằng 54

câu 4:42-(2x+32)+12:2 bằng 6

Answer 1

\(7\left(x-9\right)=35\Leftrightarrow x-9=5\Leftrightarrow x=14\)

Câu 2:  \(2^x=2^2\cdot2\Leftrightarrow2^x=2^3\Leftrightarrow x=3\)

Câu 3: \(2\cdot3^{x-1}=54\Leftrightarrow3^{x-1}=27\Leftrightarrow3^{x-1}=3^3\Leftrightarrow x-1=3\Leftrightarrow x=4\)

Câu 4: \(42-\left(2x+32\right)+12:2=6\)

      \(\Leftrightarrow42-2x-32+6=6\)

      \(\Leftrightarrow-2x=6-6+32-42=-10\)

      \(\Leftrightarrow x=5\)

Answer 2

Cau 1: 7.(x-9)=35

x-9=35:7

x-9=5

x=5+9

x=14

Cau2: 2:2^x=2^2.2

2:2^x=8

2^x=8.2

2^x=16

=> x=4

 

 

Answer 3

Cau 3: 2.3^x-1=54

3^x-1=54:2

3^x-1=27

3^x-1=3^3

=> x-1=3

x=3+1

x=4

Cau4: 42-(2x+32)+12:2=6

(2x+32)+6=42-6

(2x+32)+6=36

2x+32=36-6

2x+32=30

2x=30-32

2x=-2

x=-2:2

x=-1