How do i solve the following (^2 means that 2 is the exponent)

7a^2-17a-3a^2+2a

There are like terms in this problem. It looks scary but if we combine our like terms it makes it a lot easier. Also, like terms are terms with the same variables that are at the same power. 

So add 7a^2 and -3a^2

You'll get the following sum: 
4a^2

Add -17a and 2a 

You'll get the following sum: 
-15a

So our new problem looks like this: 

4a^2 - 15a = 0 

Factor out the variable "a." Leaving you with this: 

We can rewrite the problem like this: 
4a^2 - 15a + 0 = 0 

Now we can use the quadratic equation!



Where +/- is simply the add or divide symbol. Now let's plug in our numbers!



Simplifying a bit you get the following function: 


sqrt(225) = 15

15 + 15 = 30
30 / 8 = 15/4

15 - 15 = 0
0 / 8 = 0 

Your two answers are: 
15/4 and 0 

The answer would be c

If i think this is what your asking, he should look at the grams or pounds/ounces and compare the to their cost then max can identify which one is proportional and which is not ( i think xd)