Question 54028
say ~>
x = amount of hours worked after school
y = amount of hours worked on saturday
{{{x + y = 13}}} or {{{x = 13 - y}}}
and
{{{3x + 4y = 43}}}
plug:
{{{3(13 - y) + 4y = 43}}}
{{{39 - 3y + 4y = 43}}}
{{{y = 4}}}
plug:
{{{x = 13 - y}}}
{{{x = 13 - 4 = 9}}}
9 hours worked after school and 4 hours worked on saturday