Question

5^x+5^x+3=630

Answer 1

`5^x+5^(x+3)=630`

`=>5^x+5^x*5^3=630`

`=>5^x*(1+5^3)=630`

`=>5^x*126=630`

`=>5^x=630:126`

`=>5^x=5`

`=>5^x=5^1`

`=>x=1` 

Answer 2

     \[
     5(1) + 5^{(1+3)} = 5 + 5^4 = 5 + 625 = 630
     \]
     \[
     5 + 625 = 630
     \]

Vây x = 1