To solve these type of questions, you need to create 2 equations that represent the two statements given. So for "One number is 5 times more than the other." You'll make

And for "The sum of the numbers is 17" you would make:

What you would do after this is put the value of y, x + 5, into the second equation. This gets the x alone, allowing you to solve for x.

Then you plug back the value into one of the equations like this:

So your numbers would be 6 and 11.