Question

At Pontotoc Middle School there are only

7th and 8th graders. There are 15x + 13xy + 10y
students. There are 8x + 8xy + 8y 8th graders.
How many 7th graders are there?

Answer 1

7x + 5xy + 2y is the number of 7th graders in the school.

Explanation:

We are told that the total number of students is 15x + 13xy + 10y for both, 7th and 8th grade. We are also told that there are 8x + 8xy + 8y 8th graders. Incase you weren't able to figure out by this detail, we need to subtract to find the answer. We need to subtract the total students, 15x + 13xy + 10y, from the 8th graders, 8x + 8xy + 8y.

The steps would look like this:

15x + 13xy + 10y

— 8x + 8xy + 8y

---------------------------

7x + 5xy + 2y

15 - 8 = 7

13 - 8 = 5

10 - 8 = 2

Answer 2

So what we need to do is find out how many are left after taking away the 8th graders.

15x - 8x = 7x

so we have part of that

7x

Then 13xy - 8xy

5xy

10y - 8y

2y

this means that for 7th graders its

7x + 5xy + 2y

Explanation: