anonymous one year ago given f(x)=-x^2+2x, find f(-3) will medal and fan :3

1. Nnesha

f(-3) that means x =-3 so substitute x for -3 into f(x)=-x^2+2x

2. anonymous

f(-3)=-3x^2+2(3)

3. anonymous

i didn't mean that x after 3...

4. Nnesha

alright it should be -(-3)^2+2(-3) now solve this

5. anonymous

-(-9)+-6

6. Nnesha

when you take even power of negative number you will always get positive answer

7. anonymous

so 9+6?

8. Nnesha

$\huge\rm -\color{ReD}{x}^2+2\color{ReD}{x}$this is the function replace x with -3 $\huge\rm -(\color{ReD}{-3})^2+2(\color{ReD}{-3})$ 2 times -3 = ?

9. anonymous

-6

10. Nnesha

yes right $-(-3)^2-6$ solve

11. anonymous

9-6=3

12. Nnesha

(-3)^2 = 9 there is a negative sign front of the parentheses

13. anonymous

but you said two negatives make a positive????

14. Nnesha

yes right so (-3)^2 = -3 times -3= 9

15. anonymous

i got 9 and i plugged it into the equation and that's how i got 3

16. Nnesha

$\huge\rm\color{blue}{ -}\color{ReD}{x}^2+2\color{ReD}{x}$this is the function replace x with -3 $\huge\rm \color{blue}{-}(\color{ReD}{-3})^2+2(\color{ReD}{-3})$ $\huge\rm \color{blue}{-}(\color{ReD}{9})-6$ (-3)^2 =9 but i'm saying blue sign would stay there

17. Nnesha

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18. anonymous

ohh okay i see what you're saying now..

19. anonymous

do you -(9)-6? or is that the answer?

20. Nnesha

yes right

21. anonymous

Thank you

22. Nnesha

$$\color{blue}{\text{Originally Posted by}}$$ @Justmeneedinghelp do you -(9)-6? or is that the answer? $$\color{blue}{\text{End of Quote}}$$ yes solve that

23. Nnesha

np

24. anonymous

@Nnesha i got -15 is that right?

25. Nnesha

yes right

26. anonymous

okii thanks again

27. Nnesha

yw