Question

tìm x, nếu

a, 3^x : 3 = 9

b, 2(x-1)⁵ + 2 = 4

c, 4^2x-1 : 2² = 16

d,707 : [(2^x - 5) + 74] = 4² - 3²

Answer 1

3^x : 3 = 9

3^x = 9 . 3

3^x = 27

3^x = 3³

=> x = 3

c. 4^{2x - 1} : 2² = 16

    4^{2x - 1} = 16 . 2² 

    4^{2x - 1} = 64

    4^{2x - 1} = 4³

=> 2x - 1 = 3

=> 2x = 3 + 1

=> 2x = 4

=> x = 2

Answer 2

a,3

b,2

c,2

d,5

Answer 3

a, 3^{x :}3=9

3^x =9:3

3^x=3¹

=>x=1

\(b,2\left(x-1\right)^5+2=4\)

\(2\left(x-1\right)^5=4-2\)

\(2\left(x-1\right)^5=2\)

\(\left(x-1\right)^5=2:2\)

\(\left(x-1\right)^5=1\)

\(\Rightarrow x=2\)

\(c,4^{2x-1}:2^2=16\)

\(4^{2x-1}:4=16\)

\(4^{2x-1}=16.4\)

\(4^{2x-1}=64\)

\(4^{2x-1}=4^3\)

\(\Rightarrow2x-1=3\)

\(2x=3+1\)

\(2x=4\)

\(x=4:2\)

\(x=2\)

\(d,707:[\left(2^x-5\right)+74]=4^2-3^2\)

\(707:\left[\left(2^x-5\right)+74\right]=16-9\)

\(707:\left[\left(2^x-5\right)+74\right]=7\)

\(\left(2^x-5\right)+74=707:7\)

\(\left(2^x-5\right)+74=101\)

\(2^x-5=101-74\)

\(2^x-5=27\)

\(2^x=27+5\)

\(2^x=32\)

\(2^x=2^5\)

\(\Rightarrow x=5\)

Answer 4

sorry mk lm nham cau a

3^x:3=9

3^x=9.3

3^x=27

3^x=3³

=>x=3

Answer 5

\(3^x:3=9\)

\(3^x=27=3^3\)

\(=>x=3\)