Question 800873
x for length
y for width


x=3y;
If x+6 and y+5, (not sure if means by units or "times"), then x+6=2(y+5).


System of Equations:
{{{x=3y}}} and {{{x+6=2(y+5) }}}
Simplify second equation,
{{{x+6=2y+10}}}
{{{x-2y=4}}}.
Substitute using the x formula:
{{{(3y)-2y=4}}}
{{{highlight(y=4)}}} meaning {{{x=3*y=3*4=highlight(12)}}}