Hey there!
2y - 12 is completely simplified. Now, we have to simplify 1/4(8y-12) using the distributive property, which is defined as:
a(b + c) = ab+ac
Therefore, we have: 1/4(8y) - 1/4(12)
Now for some vocabulary. The word of means multiplication. We have here 1/4 of 8y, and 1/4 of 12. Which means we have 1/4 times 8y = 2y, and 1/4 of twelve which equals 3.
That gives us 2y - 3
That proves that they're not equivalent.
Hope this helps!