Question 881698
n, d, q, for nickels, dimes, quarters.


{{{d=-1+2n}}};
{{{n+d+q=25}}};
{{{0.05n+0.10d+0.25=4.90}}};
Changing to adjust the form of the first equation,
{{{-2n+d=-1}}}
{{{2n-d+0q=1}}}



Resulting Matrix:
{{{(matrix(3,4,
2,-1,0,1,
1,1,1,25,
0.05,0.1,0.25,4.9))}}}


Best to multiply the third row by 100 so you have all integers for the matrix:
{{{(matrix(3,4,
2,-1,0,1,
1,1,1,25,
5,100,25,490))}}}


... and divide row 3 by 5 to have the smallest integers:
{{{(matrix(3,4,
2,-1,0,1,
1,1,1,25,
1,20,5,98))}}}


Can you continue what you need to do from here?