Answer:
![f(x)=5x+50](https://img.qammunity.org/2020/formulas/mathematics/middle-school/klywm8vidwpw4cln8xilj5fjc00cks0ewd.png)
![f(11)=105](https://img.qammunity.org/2020/formulas/mathematics/middle-school/itl0dqrju8mew1bmoe1l3t91e7ws5tklqk.png)
Explanation:
Let x represent number of cars Greg washes and f(x) represent Greg's total income.
We have been that Greg's dad pays him $50 plus $5 for each car that he washes.
The earnings for washing x cars would be
.
The total earnings for washing x cars would be
.
Therefore, the function
represents Greg's total income as a function of the number of cars he washes.
To find the Greg's total income from washing 11 cars, we will substitute
in our function.
![f(x)=5x+50](https://img.qammunity.org/2020/formulas/mathematics/middle-school/klywm8vidwpw4cln8xilj5fjc00cks0ewd.png)
![f(11)=5(11)+50](https://img.qammunity.org/2020/formulas/mathematics/middle-school/e0amk20e4ttw0yqlrvtxwfy5f6ei34oif4.png)
![f(11)=55+50](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jbdry3krrsrj4rlcyn8u2u38lwqfvtfqbi.png)
![f(11)=105](https://img.qammunity.org/2020/formulas/mathematics/middle-school/itl0dqrju8mew1bmoe1l3t91e7ws5tklqk.png)
Therefore, Greg earned $105 last Saturday.