Question 29077
The x-intercepts occur when the value of y is zero.
When trying to solve any equation - the first thing we should do is try to pull out what the terms have in common (if possible). For this equation, we can pull out (or factor out) a -2 to get:
               y = -2(x^2 + 4x - 10)
Next we see if the expression within the parenthesis can be factored (by a reverse FOIL method). This expression can not be factored. We can not find factors of 10 that subtract to be 4. So we must use the quadratic formula:

*[invoke quadratic "x", 1, 4, -10]


REMEMBER: you can always check your solutions by plugging the number back into the equation. Since the solutions are decimals, the number you get when you plug in the solution will be close to zero.