What is the equation of the trend line in the scatter plot?

First one Equivalent but not simplified fully (Can combine the two y terms)

Second: Equivalent but not simplified fully (Can combine the two x^2 terms)

Third: Equivalent and simplified fully

Fourth: Not equivalent (y term is not correct)

Fifth: Not equivalent (x^2 term is not correct and the constant terms [ones without variables] can be combined)

Sixth: Not Equivalent (y term is not correct and the constant terms can be combined)

Step-by-step explanation:

You just need to know if two terms have the same variable they can be added or subtracted.  But if it is say x and x^2 it cannot, they need to be brought to the same power as well.  or if there is a term with xy, it can only be added and subtracted to other xy terms