Question

Tìm x:

a)70 - 5 (x - 3) = 45b)3^x - 12 = 15c)3^x+2 +2.3^x = 3³³ .33

 

 

Answer 1

a) 70 - 5 ( X-3)=45

5(x-3)=70-45

5(X-3)= 25

x-3=25:5

X-3=5

X=5+3=8

B) 3^x-12=15

3^x=12+15

3^x=27

3^x=3^3

=>x = 3

Answer 2

Tiếp phần kia

c) bn làm như sau:

 

Answer 3

a) \(70-5\left(x-3\right)=45\)

\(5\left(x-3\right)=70-45=25\)

\(x-3=\frac{25}{5}=5\)

\(x=8\)

b) \(3^x-12=15\)

\(3^x=15+12=27=3^3\)

\(\Rightarrow x=3\)

c) \(3^{x+2}+2\cdot3^x=3^{33}\cdot33\)

\(3^x\left(3^2+2\right)=3^{34}\cdot11\)

\(3^x\cdot11=3^{34}\cdot11\)

\(3^x=3^{34}\)

\(\Rightarrow x=34\)

Answer 4

a) 70-5.(x-3)=45

5.(x-3)=70-45

5.(x-3)=25

x-3=25:5

x-3=5

x=5+3

x=8

b) 3^x-12=15

3^x=15+12

3^x=27

=> 27 = 3³ → x=3