Question 1050005
your equations are
1.{{{N+D+Q=35}}}

2.{{{N=5+D}}}

3.{{{5N+10D+25Q=600}}}



simplify

{{{2D+Q=30}}}

{{{15D+25Q=575}}}




*[invoke linear_substitution "D", "Q", 2, 1, 30, 15, 25, 575]