Question

Tìm x biết

a) 5^x . ( 5³ )² = 625

b) ( 5x + 1 )² =36/49

c) ( 8x - 1 )^{2n + 1} = 5 ^{2n + 1}

Answer 1

a) \(5^x\cdot5^6=5^4\)

\(5^x=5^{4-6}\)

\(5^x=5^{-2}\)

=> x = -2

Answer 2

b) \(\left(5x+1\right)^2=\left(\pm\frac{6}{7}\right)^2\)

+) 5x + 1 = 6/7

5x = -1/7

x = -1/35

+) 5x + 1 = -6/7

5x = -13/7

x = -13/35

Vậy,.........

Answer 3

c) => 8x - 1 = 5

=> 8x = 6

=> x = 3/4

Vậy,.....