Question

tim x

a, 3^x=3^2*9

b, (21+x):9=9^5:9^4

c, 5^x-1-13=613

Answer 1

3^x=3^2x3^2

3^x=3^4

Suy ra x =4

Giải 1 phần thui mệt was

Answer 2

a) 3^x = 3² . 9

3^x = 3² . 3²

3^x = 3⁴

=> x = 4

b) ( 21 + x ) : 9 = 9⁵ : 9⁴

(21 + x ) : 9 = 9

21 + x  = 9 . 9

21 + x = 81

x = 81 - 21

x = 60

c) 5^x + 1 - 13 = 613

5^x = 613 + 13 - 1

5^x = 625

5^x = 5⁴

=> x = 4

Answer 3

a)\(3^x=3^{^{ }}^2.9\)

\(3^x=3^2.3^2\)

\(3^x=3^{2+2}=3^4\)

\(\Rightarrow x=4\)

b)\(\left(21+x_{ }\right):9=9^5:9^4\)

\(\left(21+x\right):9=9^{5-4}=9\)

\(21+x=9.9\)

\(x=81-21=60\)

c)\(5^x-1-13=613\)

\(5^x-\left(1+13\right)=613\)

\(5^x=613+14=625\)

\(5x=5^4\)

\(\Rightarrow x=4\)