Seven more than twice a number is equal to 25. Which of the following is the number? Use algebra to find your answer and show your work.

Answer 1

We are looking to find an unknown number, so let's let x = the unknown number.

The problem says that SEVEN more than TWICE "a number" is equal to 25.

So, TWICE the unknown number means that we are going to multiply the unknown number by 2 (2 times or twice mean the same thing)

The first thing we know for sure then is that we will have 2 times X

It also says SEVEN MORE THAN which means that we will be adding 7.

So, now we know that we will have 2 times X plus 7

And, finally, it says "is equal to 25", so 2 times X plus 7 equals 25

2x + 7 = 25

Now we solve by undoing the mathematical operations used in this equation.

So, instead of adding 7, in order to "undo" the addition of 7, we will subtract 7 from both sides.

2x + 7 = 25

-7 -7

and we are left with

2x = 18

To "undo" the multiplication of 2 we will divide both sides of the equation by 2, so

2x = 18

÷2 ÷2

We end up with our solution which is that x = 9