Question 148590
1.{{{-7x+y=20}}}
2.{{{9x-3y=36}}}
Use eq. 1 to solve for y in terms of x.
1.{{{-7x+y=20}}}
{{{y=20+7x}}}
Now substitute this expression into eq. 2 and solve for x.
2.{{{9x-3y=36}}}
{{{9x-3(20+7x)=36}}}
{{{9x-60-21x=36}}}
{{{-12x=96}}}
{{{x=-8}}}
Now back substitute to find y.
{{{y=20+7x}}}
{{{y=20+7(-8)}}}
{{{y=20-56}}}
{{{y=-36}}}