The pre-image is...
What does a pre image mean

I forgot what the letter was for this option but The Pre image is a geometric shape BEFORE a transformation occurs ( I think that's option B but u should read it to be sure)

Step-by-step explanation:

Hope this helps I was kinda paying attention

i think it means pre image (plural pre images) (mathematics) For a given function, the set of all elements of the domain that are mapped into a given subset of the codomain; (formally) given a function ƒ : X → Y and a subset B ⊆ Y, the set ƒ−1(B) = {x ∈ X : ƒ(x) ∈ B}. The pre image of under the function is the set .

Step-by-step explanation:

First line because 4(2a+1)=8a+4 and 9a+4-(8a+4)= a

Second line because a times 2 =2a and 2a+1-2a=1

Although the second equality is more or less obvious since 2a+1 leaves a remainder of 1 when divided by a.