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Mathematics 7 Online
OpenStudy (vera_ewing):

Write a polynomial function with the given roots

OpenStudy (vera_ewing):

OpenStudy (fibonaccichick666):

so before you even type it, what does it mean when you have a root?

OpenStudy (vera_ewing):

Basically the 0 of the polynomial?

OpenStudy (fibonaccichick666):

yea, it means at that point, y=0

OpenStudy (fibonaccichick666):

so, what do we know that whenever we multiply by it, we get zero?

OpenStudy (vera_ewing):

So for the polynomial we have to write, y has to equal 0 at 7 AND 10?

OpenStudy (vera_ewing):

Anything multiplied by 0 is 0

OpenStudy (fibonaccichick666):

yep yep

OpenStudy (fibonaccichick666):

so now, what's the easiest equation where x=7 that y will equal zero?

OpenStudy (vera_ewing):

I have no idea, that's where I'm stuck

OpenStudy (fibonaccichick666):

ok, so what's 2-2?

OpenStudy (vera_ewing):

0

OpenStudy (fibonaccichick666):

ok, how about 7-7?

OpenStudy (vera_ewing):

0

OpenStudy (fibonaccichick666):

so, at x=7, what will x-7 equal?

OpenStudy (vera_ewing):

0

OpenStudy (vera_ewing):

Ohhh I get it!

OpenStudy (fibonaccichick666):

right, now stick that in parentheses

OpenStudy (vera_ewing):

(x-7) - (x-10)? Would that work?

OpenStudy (fibonaccichick666):

can't be subtraction

OpenStudy (vera_ewing):

How do we incorporate the 10?

OpenStudy (fibonaccichick666):

what function do we know for a fact we can always use to get a zero

OpenStudy (fibonaccichick666):

hint, I brought it up above

OpenStudy (vera_ewing):

Multiplication? Anything times 0 is 0?

OpenStudy (fibonaccichick666):

right!

OpenStudy (fibonaccichick666):

so you were good with the x-10 part

OpenStudy (vera_ewing):

So (x-7)(x-10)?

OpenStudy (fibonaccichick666):

but not the subtraction sign in the middle

OpenStudy (fibonaccichick666):

good, now you must have an equals sign

OpenStudy (fibonaccichick666):

and something on the other side of said equals sign

OpenStudy (vera_ewing):

(x-7)(x-10) = y

OpenStudy (fibonaccichick666):

yay!

OpenStudy (fibonaccichick666):

You fixed it yourself :)

OpenStudy (vera_ewing):

Got it! Thanks so much :)

OpenStudy (fibonaccichick666):

np, you did it!

OpenStudy (vera_ewing):

:D

OpenStudy (fibonaccichick666):

so, for when you are on a test or something where you can't get help, start by thinking of definitions. What does this mean? What do they want? Once you figure than out, it becomes a lot easier. :) Best of luck! Keep on learning!

OpenStudy (vera_ewing):

Alright, thank you for the helpful advice :)

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