What do you need help with?
This question is quite simple really. They are basically asking you to combine like terms. You have two different figures with the variable y, so you just combine the them. It would then be 3x + 2y. You cannot simplify this equation any further since there is nothing to solve for or anymore like terms to combine.
16, because all the other numbers are divisible by 3.
Or it could be 6 because it only has one digit while the others have 2
The rate of change is simply the derivative of a function with respect to the other variable. In this case the rate of change with respect to x is desired. Therefore
f(x) = x^3 - 3x^2
f'(x) = 3x^2 - 6x
therefore the rate of change of y with respect to x is dy/dx = 3x^2 - 6x
Step 2 9y - 24 = 10 + 3y because 3 times 3y its not 6y nor is 3 times 8 equal to 5
