Answer: D, 2 and -1
Explanation: To find the zeros of this quadratic function, we can factor or use the quadratic formula.
FACTORING: We need to find 2 numbers that add up to -1 (the coefficient for -x in this function) and multiply to -2 (the constant in this function). -2+1 = -1 and -2•1 = -2. Therefore x^2-x-2 can be factored into f(x)=(x-2)(x+1). To find the zeros, set each factor to zero (x-2=0 and x+1=0) and solve for x. You get 2 and -1.
QUADRATIC FORMULA: The coefficient in x^2 is 1 (a in the quadratic formula), the coefficient of -x is -1 (b in the quadratic formula), and -2 is c in the quadratic formula. Plug all of this into the formula and you get the following: -(-1) plus or minus the square root of (-1)^2 - 4(1)(-2) all over 2(1). Simplify this and you get 1 plus or minus the square root of 9 all over 2. (1+3)/2 is your first zero, 2. (1-3)/2 is your second zero, -1.