## KiArUnsYu 3 years ago What is the range of the graph of y = −2x2 − 8x − 7? y ≥ 1 y ≤ 1 y ≤ −2 All real numbers

1. Mr.Me

\[y=-2x ^{2}-8x-7\] is this the equation?

2. Mr.Me

if so you need to find the maximum or minimum value of this function. It is quadratic so it will be a parabola and upside down since the x^2 term is negative

3. KiArUnsYu

how do you find the range?

4. Mr.Me

The range is all the possible values of y. so since this is a parabola there will be a maximum for y but no minimum. Do you know how to calculate derivatives/

5. KiArUnsYu

ohh no.

6. Mr.Me

do you have a graphing calculator?

7. KiArUnsYu

yes

8. Mr.Me

so 1. graph this equation 2. press 2nd and hit the trace button. 3.Choose option number 4 4. move the cursor to the left of the highest point on the graph and press enter 5. move the cursor to the right of the highest point and press enter 6. press enter again 7. look on the bottom of the screen you will see an x= and y= the y value is the maximum value of y and the range is that value and everything else below it. Let me know what you get

9. KiArUnsYu

y less than or equal to 1?

10. Mr.Me

YUP

11. KiArUnsYu

yay!! thanks!