You can put this solution on YOUR website! The linear term is x^1 to the first power.
3x^2+5x+12=0
5x is the linear term
4x^2-64=0
There is no linear term. no x^1 term
PS Stop shouting.
All caps is considered shouting on the internet.
It is rude and annoying and makes it harder to read.
It also draws too much attention to the words. It is not good attention.