iheartfood 3 years ago Solve the polynomial equation... (inside!) Please show work!! and explain! Thanks!! :)

1. iheartfood

|dw:1352180620990:dw|

2. .Sam.

You have to find one root, then use long division to factor the polynomial.

3. iheartfood

can u please show me how? idk how to find it :(

4. .Sam.

Are you allowed to use a scientific calculator in your exams?

5. iheartfood

yes I'm allowed to :) this is a practice worksheet and i need to show my work :/ and idk how to solve much less show work lol :/

6. iheartfood

do u understand how to solve this? cuz i am lost :(

7. .Sam.

I would use trial an error from calculator, you key the equation into your calculator, then substitute any number for x and see if its equal to zero, if that value of x equals to zero, then that is the factor of the polynomial

8. .Sam.

Ok, according to the trial an error, x=8 works, so, f(8)=15(8)^3-119(8)^2-10(8)+16=0

9. .Sam.

Now, x=8, (x-8) is a factor of that polynomial. then use this to find other factors, by long division.

10. iheartfood

so, what exactly am i dividing?? and can you please type or draw out all the work in order?? :) i understand better that way :)

11. .Sam.

You are dividing (x-8)

12. .Sam.

Because x=8 for the f(x) is zero

13. iheartfood

okay, so I'm dividing 15x^3-119x^2-10x+16 divided by x-8?

14. .Sam.

Yes

15. iheartfood

k i got 15x^2+x-2... so is that my answer?? :)

16. iheartfood

17. .Sam.

yes

18. iheartfood

kk thanks! :)

19. iheartfood

can u pls help me with another one>? :)

20. .Sam.

But if they tell you to solve, that means you have to find x from 15x^2+x-2

21. .Sam.

Use factor or quadratic equation or completing the square to solve 15x^2+x-2

22. iheartfood

kk thanks!! :)

23. .Sam.

welcome