Help me 1 to 5 please show work please

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Ariel is working at a meat packing plant for 5 nights a week. her regular wage is $11 an hour. she earns tine and a half for any overtime hours. this week she worked 9 hours of over time .how much will ariel earn for overtime this week ?

Which of the following is best modeled using a linear equation y=ax+b, where a is less than 0?