Question 159428
<pre><font size=4><b>
{{{47-x=17y}}} ------------------------------------> eqn 1
{{{23y+81=-3x}}} ----------------------------------> eqn 2
In eqn 1, we get
{{{47-17y=x}}} -------------------------------------> eqn 3, subst. in eqn 2
{{{23y+81=-3(47-17y)}}}
{{{23y+81=-141+51y}}} combine similar terms
{{{81+141=51y-23y}}}
{{{222=28y}}} ------> {{{cross(222)7.92857/cross(28)= cross(28)y/cross(28)}}}
{{{y=7.92857}}}
Go back eqn 3:
{{{x=47-17*7.92857=47-134.7857}}}
{{{x=-87.7857}}}
In doubt? go back eqn 2:
{{{23(7.92857)+81=-3(-87.7857)}}}
{{{182.3571+81=263.3571}}}
{{{263.3571=263.3571}}}
Thank you,
Jojo</pre>