Answer:

Explanation:
Let be "x" the number mentioned in the exercise.
"Seven times a number" indicates a multiplication. Then, this can be written in this form:

And "Six time the number" is:

Finally, it is important to remember that the sum of two numbers is obtained by adding them. In this case the exercise says "The sum of seven times a number, and 3, is equal to six times the number", therefore, we can write the following expression:
