The expression 20l + 25g - 10 gives the number of dollars that jose makes from mowing l lawns and raking g gardens.
how many dollars does jose make from raking 4 gardens and mowing 3 lawns?

If Jose mows 3 lawns and rakes 4 gardens, he makes 20l+25g-10
                                                                                    =20(3)+25(4)-10
                                                                                    =60+100-10
                                                                                    = $150