Answer :
[tex]\text{Turn the scenarios into equations. "x" represents the amount of hours}\\\\\text{Mowing lawns:}\\\\y=8.80x \\\\\text{Babysitting:}\\\\y=7.70x\\\\\text{Plug in values and add:}\\\\8.80(6)+7.70(3)\\\\52.80+23.10\\\\\boxed{\$75.90}[/tex]