Given from the question
first fraction = 5/6
second fraction = 1/3
We're asked what's the difference between the fraction
First, we need to equalize the denominator to the same number. The first denominator is 6, the second denominator is 3. I'd like to make them both 6. So the second denominator needs to be multiplied by 2, so does the numerator
second fraction = 1/3
second fraction = (1 × 2)/(3 × 2)
second fraction = 2/6
Second, we have new fractions which have the same denominator. Calculate the difference
d = first fraction - second fraction
d = 5/6 - 2/6
d = 3/6
The red tape is 3/6 yard more than the green tape.
To solve this, you distribute the -y to both terms, 2 and 4y.
It will look something like this: (2*-y)+(4y*-y)
When you simplify, look for any like terms that can be combined, and if none, then leave it as it is.
Your final answer will be: -2y-4y^2
Is it

or

?
both start out the same, just remember what you do to one side you have to do to the other, so subtract both sides by 1/4, then you want to get y alone, so either divide or multiply the 3 on both sides! let me know which it is and I can help you out more
[edit] it's the second, and not going to use cross multiplication.
added a picture that walks you through it :)