Question 1012061
Let's say our number of dimes is represented by the variable d, and quarters by the variable q. 

If the number of quarters exceeds that of dimes by 8, we have the equation {{{q=d+8}}}.

We also have numeric values. Since a quarter is worth 25 cents, the total value is 0.25q. The same applies for dimes with 0.10d. We are told it adds to 17.60, so we have the equation {{{0.25q+0.10d=17.60}}}

We now have a system of linear equations. You can solve this with substitution.
*[invoke linear "d", "q", 1, -1, 8, 0.1, 0.25, 17.6 ]
*[invoke linear_substitution "d", "q", 1, -1, 8, 0.1, 0.25, 17.6 ]