Question 744667
Hi there....don't worry we'll get through it! Here we go. 
 
What we need to do is factor x^2-4. This equation is what we call a perfect square binomial which means we will have two binomials(expressions with terms of 2 different degrees, example:4 has a degree of 0, x^2 has a degree of 2) that are opposites (one number is positive and one number is negative but the have the same constant) of each other that equal x minus the square root of our constant term. So when factor, we should get (x-2)(x+2) because the square root of 4 is 2. Also -2 and 2 are opposites(one is positive, one is negative). We can check our factoring to make sure it is correct by using the FOIL(first, inner, outer,last) method. So what we are going to do is multiply the first two terms, x and x, together. When we multiply we get x^2. next we multiply the outer terms x and -2 together to get-2x, then we multiply our inner terms, 2 and x to get 2x and our last terms, -2 and 2, to get -4. We can add -2x and 2x, and they cancel, so we are left with x^2-4, which is our original binomial. That means that our final answer for y is y=(x-2)(x+2). Good luck, hope this helps(sorry it was so long!)and let me know of any other questions. :)