Question 974752
Not the whole solution but just part of the process of solving:


n, q, d for nickels dimes quarters,


{{{system(n+d+q=42,0.05n+0.1d+0.25q=7.15,n+d=-2+q)}}}


{{{system(n+d+q=42,n+2d+5q=143,q=n+d+2)}}}


Substitute for q.
{{{system(n+d+n+d+2=42,n+2d+5(n+d+2)=143)}}}
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Simplify this two-variable system, and solve for n and d.