Question 708336
Since (f)x = –2x + 4 and g(x) = –6x – 7 and you want to find f(x) - g(x), just replace f(x) with -2x+4 and g(x) with -6x-7:
f(x) - g(x)
(-2x+4)-(-6x-7)
[Important! Notice the use of parentheses! It is an extremely good habit to use parentheses with making substitutions (especially if you are substituting in multiple terms like we are here).]<br>
Since subtractions cause problems (they are harder than additions and they are not commutative so you can't change the order), I am going to change the subtractions to additions of the opposite:
(-2x+4)-(-6x+(-7))
(-2x+4)+(6x+7)  (Note how the signs changed for both terms in the parentheses that had the "-" in front!)
Since we now have all addition we can freely change the order and grouping of the terms. Reordering and grouping the like terms together we get:
(-2x+6x)+(4+7)
Adding the like terms:
4x+11<br>
So f(x) - g(x) = 4x+11