Question 817996
X^2+3X-4-X+5
Here you have 5 terms:x^2, 3x, -4, -x and 5

With the information given here, there is one type of thing you can do, and that is to combine like terms.
The like terms are 3x and -x, and -4 and 5. 
There is nothing you can combine x^2 with because there are no other terms with x^2 in them.
3 times the value of x, minus the value of x once gives you 2 times the value of x (or 2x). 
You can draw this to vizualize it if you need help. If one box represents the value of x, draw 3 boxes. Then subtract the value of 1 x, so you cross out a box and are left with 2 boxes.
-4 + 5 = 1 (Remember writing a negative like -7 is the same as adding a negative, because adding a negative amount means you are taking away.)
So the answer is x^2 + 2x + 1