Question

tìm x

a) (x+3)mũ 2= 16

b) 3.2mux x+1= 96

c) 3(x-5)mũ 2= 27

d) 2 mũ x .5 = 80

Answer 1

a. (x + 3)² = 16

    (x + 3)² = 4²

     x + 3    = 4

           x    = 4 - 3

           x    = 1

b. (3.2)^x+1 = 96

2^x+1          = 96 : 3

2^{x + 1}        = 32

2^x+1          = 2⁵

x +1          = 5

x               = 5 - 1

x               = 4

c. 3(x - 5)²  = 27

(x - 5)²        = 27 : 3

(x - 5)²        = 9

(x - 5)²        = 3²

x - 5            = 3

x                 = 3 + 5

x                 = 8

d. 2^x. 5 = 80

2^x         = 80 : 5

2^x        = 16

2^x         = 2⁴

x           = 4

Answer 2

a) \(\left(x+3\right)^2=16\)

 \(\left(x+3\right)^2=4^2\)

 \(x+3=4\)

 \(x=4-3=1\)

Vậy x = 1

b) \(\left(3.2\right)^{x+1}=96\)

 \(\left(3.2\right)^{x+1}=2^5.3\)

 \(2^{x+1}=2^5\)

  \(x+1=5\)

 \(x=5-1=4\)

 Vậy x = 4

c) \(3\left(x-5\right)^2=27\)

 \(\left(x-5\right)^2=9\)

 \(\left(x-5\right)^2=3^2\)

 \(x-5=3\)

 \(x=5+3=8\)

Vậy x = 8

d) \(2^{\left(x.5\right)}=80\)

 \(1^{\left(x.5\right)}=40\)

 \(x.5=2^3.5\)

\(x=2^3=8\)

Vậy x = 8