U should add a picture to solve it
4/5 is NOT a multiple of 1/4 because the denominators are not divisible by each other.
If the tax was 10%, then you’d end up paying the original 100% plus the additional 10% tax, so you’d pay 110% of the original price.
In your example, it’s the same, except you have 8.25% tax, so you’d pay 100%+8,25% or 108.25% of the original price.
That’s stated as a percent.
To convert a percent to a decimal, you divide by 100:
108.25 ÷ 100 = 1.0825
To convert a decimal to a fraction, you have to know the place value of the smallest place. In this case, the 5 is in the ten thousandths place.
10825/10000
You can always double check that fraction on a calculator.
Answer:
b. 
a. ![\displaystyle [8x + 12y]^2 + [6x + 9y]^2 = [10x + 15y]^2](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5B8x%20%2B%2012y%5D%5E2%20%2B%20%5B6x%20%2B%209y%5D%5E2%20%3D%20%5B10x%20%2B%2015y%5D%5E2)
Step-by-step explanation:
b. 
a. ![\displaystyle [8x + 12y]^2 + [6x + 9y]^2 = [10x + 15y]^2](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5B8x%20%2B%2012y%5D%5E2%20%2B%20%5B6x%20%2B%209y%5D%5E2%20%3D%20%5B10x%20%2B%2015y%5D%5E2)
The two expressions are identical on each side of the equivalence symbol, therefore they are an identity.
I am joyous to assist you anytime.