Answer:
The answer is:
\(15+7x=99\\x=12\)
Step-by-step explanation:
In order to determine the answer, we have to know about equations.
We use equations when we have to express a problem with variables and values. In this case, we have one variable that expresses "the number" that is mentioned in the statement.
It is important to declare that there is a sequence of resolve the math operations. First it is the multiplying and then the addition.
In this case:
x="a number"
\(15+7x=99\\7x=99-15\\7x=84\\x=12\)
Finally, we have the following equation of the problem and its solution:
\(15+7x=99\\x=12\)
