Answer:
The domain is 
Step-by-step explanation:
Given functions
and 
Subtract these two functions:

Plot these difference on the coordinate plane (see attached diagram). This function is defined for all vlues of x, so the domain is 
Like terms are going to have the EXACT same variables....or they can just be constants with no variables.
x^2 and 3x^2 are like terms
x^2 and x^3 are not like terms
8 and 9 are like terms
8x and 9y are not like terms
so ur like terms in ur problem are : 2y^3 and y^3
-7 - 3x = 9x(x + 2)
Standard Form:
-9x^2 - 21x - 7 = 0
To easily find the slope and y intercept of the line, put it in slope intercept form by rearranging the variables around.
6x-7y = 2
6x - 7y + 7y = 2 + 7y
6x = 7y + 2
6x - 2 = 7y + 2 - 2
7y = 6x - 2
7y/7 = 6x/7 - 2/7
Y = 6/7(X) - 2/7
Y = 6/7x - 2/7
Slope = m = 6/7
Y intercept = b = -2/7
(0, -2/7).