Question 231292
Let {{{a}}} = hourly pay baby-sitting
Let {{{b}}} = hourly pay in restaurant
given:
(1) {{{8a + 3b = 58}}}
(2) {{{2a + 5b = 40}}}
These are 2 equations and 2 unknowns, so it's solvable
Multiply both sides of (2) by {{{4}}} and 
subtract (1) from (2)
(2) {{{8a + 20b = 160}}}
(1) {{{-8a - 3b = -58}}}
{{{17b = 102}}}
{{{b = 6}}}
and, since
(2) {{{2a + 5b = 40}}}
{{{2a + 5*6 = 40}}}
{{{2a = 40 - 30}}}
{{{2a = 10}}}
{{{a = 5}}}
She makes $5/hr babysitting and $6/hr at restaurant
check:
(1) {{{8a + 3b = 58}}}
{{{8*5 + 3*6 = 58}}}
{{{40 + 18 = 58}}}
{{{58 = 58}}}
OK
(2) {{{2a + 5b = 40}}}
{{{2*5 + 5*6 = 40}}}
{{{10 + 30 = 40}}}
{{{40 = 40}}}
OK