SOLUTION: What are the domain and range of the parabola of this equation? Y=-x^2-x+8 A.The domain is the set of real numbers, and the range is all real numbers less than or equal to 8

Algebra ->  Finance -> SOLUTION: What are the domain and range of the parabola of this equation? Y=-x^2-x+8 A.The domain is the set of real numbers, and the range is all real numbers less than or equal to 8      Log On


   

Question 1119726: What are the domain and range of the parabola of this equation?
Y=-x^2-x+8
A.The domain is the set of real numbers, and the range is all real numbers less than or equal to 8.25.
B.The domain is the set of real numbers, and the range is all real numbers less than or equal to 8.
C.The domain is all real numbers less than or equal to 8.25, and the range is the set of real numbers.
D.The domain is all real numbers less than or equal to 8, and the range is the set of real numbers.

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Range easier to identify if the equation is put into "vertex" form. Domain will be all real numbers, since all polynomial functions have all real numbers as their domain.

y=-x%5E2-x%2B8
-%28x%5E2%2Bx-8%29
-%28x%5E2%2Bx%2B1%2F4-1%2F4-8%29
-%28%28x%2B1%2F2%29%5E2-8%261%2F4%29
-%28x%2B1%2F2%29%5E2%2B8%261%2F4
and now you see?? Identify the MAXIMUM possible y value?


The form derived lets you see the vertex which is the maximum point for the parabola equation. Domain for this parabola is x is all real numbers; and range is the real numbers less than and equal to 8%261%2F4. The parabola is concave downward.