Question 320955
1.{{{3r -4s =0}}} 
2.{{{2r + 5s = 23}}}
From eq. 1,
{{{3r=4s}}}
{{{15r=20s}}}
Multiply eq. 2 by 4,
{{{8r+20s=92}}}
Substitute for {{{20s}}},
{{{8r+15r=92}}}
{{{23r=92}}}
{{{highlight(r=4)}}}
Then find {{{s}}},
{{{20s=15(4)}}}
{{{s=60/20}}}
{{{highlight(s=3)}}}