# High School Math : How to write an algebraic equation in pre-algebra

## Example Questions

### Example Question #1 : How To Write An Algebraic Equation In Pre Algebra

Solve for X in the following equation:

Explanation:

To solve for X, isolate X on one side of the equation.  In this case, we are required to subtract one number from X.  When we add that number to both sides of the equation, we isolate X and obtain our answer.

### Example Question #2 : How To Write An Algebraic Equation In Pre Algebra

The square root of the sum of twice a number and five is equal to the square of the difference between that number and two. Which of the following equations could be used to find the number, represented by n?

Explanation:

We need to translate this word sentence into algebra: The square root of the sum of twice a number and five is equal to the square of the difference between that number and two.

The words "is equal to" denote the equal sign. Everything before it will be to the left of the equal sign, and everything after will be on the right.

The first half of the sentence says "The square root of the sum of twice a number and five." We can represent twice the number as 2n. The sum of twice the number and five can be represented by 2n + 5, because "sum" denotes addition. We need to take the square root of the quantity 2n + 5, which we can write as . The left side of the equation will be .

On the right side, we need to find the square of the difference between n and 2. "Difference" tells us to subtract, so we can represent this as n - 2. If we take the square of this quantity, we can represent this as . The right side of the equation is .

Putting both sides together with the equal sign, the entire equation is  .

### Example Question #1 : How To Write An Algebraic Equation In Pre Algebra

Which equation can be used to solve the following problem?

Jason is planning a birthday party at a bowling alley. It costs  to rent the alley and  per attendee. What is the total cost () of the party in terms of , where  equals the total number of attendees?

Explanation:

The cost per attendee, , must be multiplied by the total number of attendees and then added to the base cost, , to obtain the total cost.

### Example Question #4 : How To Write An Algebraic Equation In Pre Algebra

A family has 7 animals. Write an equation for the number of cats, , in terms of the number of dogs, . Assume the family has only cats and dogs.