For this case, the first thing we must do is define variables.
We have then:
f: number of points that fabio scored.
c: number of points that Carlos scored.
We now write the equation that models the problem:
![f = 2c - 7](https://img.qammunity.org/2019/formulas/mathematics/high-school/23gent0b029w24jp5hembh2zlm6h7embon.png)
Then, for f = 31 we have:
![2c - 7 = 31](https://img.qammunity.org/2019/formulas/mathematics/high-school/4go7ncqbu5huftlmfyl052ox5dkq28eb8n.png)
From here, we clear the number of points:
![2c = 31 + 7](https://img.qammunity.org/2019/formulas/mathematics/high-school/7stbeckp78z824tnpix7udzy8qthzjovad.png)
![2c = 38](https://img.qammunity.org/2019/formulas/mathematics/high-school/pnwcx9guioz7ia868x0rzbsvxt71y2leej.png)
![c = (38)/(2)](https://img.qammunity.org/2019/formulas/mathematics/high-school/f5crxn5axbukgvvkmg81d2y5rctxmb3tp4.png)
![c = 19](https://img.qammunity.org/2019/formulas/mathematics/high-school/5rgvf8dykyn7v26coz7e6ghbfco013y8k8.png)
Answer:
The equation to find the number of carlos points is:
![2c - 7 = 31](https://img.qammunity.org/2019/formulas/mathematics/high-school/4go7ncqbu5huftlmfyl052ox5dkq28eb8n.png)
Then, Carlos scored:
![c = 19](https://img.qammunity.org/2019/formulas/mathematics/high-school/5rgvf8dykyn7v26coz7e6ghbfco013y8k8.png)