Question

tìm x 

a/320 -(16x+4)=3².5²

b/3^x-1+3⁴=90

 

 

Answer 1

a/ 320 - ( 16 x + 4 ) = 3\(^2\). 5\(^2\)

=> 320 - 16x - 4 = 225

=> - 16x = - 91

=> x = \(\frac{91}{16}\)

b/ \(3^{x-1}+3^4=90\)

=> \(3^{x-1}+81=90\)

=> \(3^{x-1}=9\)

=> \(3^{x-1}=3^2\)

=> x - 1 = 2 

=> x = 3