Question 375428
 1.{{{y=2x}}}
2.{{{x+y=6}}}
Substitute eq. 1 into eq. 2,
{{{x+2x=6}}}
{{{3x=6}}}
{{{highlight(x=2)}}}
Then from eq. 1,
{{{y=2(2)}}}
{{{highlight(y=4)}}}