### 16 Replies to “Quadratic Functions”

1. Peter Pritchett says:

isnt 4x4x9=144? not 64

2. DrPhilClark says:

@SuperGogeta210 you are correct! I misread my own handwriting, thank you for bringing that to my attention!

3. Luis Torres says:

this might sound dumb bt whats "all real numbers" can u explain it in a simple way

4. GetOffMahBalls says:

For the Domain, would what you wrote also translate to {x|x (is an element) R}?

5. DrPhilClark says:

Yep, they would be the same ðŸ™‚

6. Luis Torres says:

umm wtf..? what do u mean all numbers are real? thats what i dont get

7. Mute Math says:

I really love this video. Awesome

8. honey Bun says:

You are GREAT!. Thank you I think I'm getting this problem on my Midterm today. God bless you and continue doing a great job. ðŸ™‚

9. The Prime Remedy says:

lefty ftw

10. mary evans says:

how did you get negative infinity, is it because the coefficient is -4?

11. DrPhilClark says:

If you are talking about for the range you are correct, since the lead coefficient is negative the quadratic will open downwards and thus the range will go to negative infinity.

12. RushParkourist says:

The answer.is wrong at 9:25
The denominator is 4 not 8
Great video btw

13. Kyle Ziegenbein says:

thanks you helped me with my IB test : )

14. Bonamana gee gee baby baby says:

I need help. plz help me solve this. Thanks you very much
IF the function f is defined by Â f = { (0,20, (1,-1), (4,6), (2,5) } and the function g is defined by g = { (-1,6), (1,0), (2,4), (4,1) } then f (g(4)) =?

15. Jaquelin Argueta says:

if ur going to write something stop erasing what you wrote before… its so annoying

16. Trevor r says:

its hard to learn past my throbbing erection