#### Question

# How do you write the quadratic function for this?

Find the quadratic function with zeros x=8 and x=9 and with coefficient at x^2 equal to 5 .

#### Answers

x = 8, x - 8 = 0

x = 9, x - 9 = 0

5*0*0 = 0, so:

5(x - 8)(x - 9) = 0

5(x^2 - 17x + 72) = 0

5x^2 - 85x + 360 = 0

So the function is:

f(x) = 5x^2 - 85x + 360

f(x) = 5x^2 - 85x + 360

you can check if its correct: 5x^2 - 85x + 360 = 0

or u can simplify it to : x^2 - 17x + 72 = 0;

hope it helps, thanks for posting this question, i love math.

(x-8)(x-9) is what you'd get out of the first 2 clues

now if you look at the third clue: coefficient of the x^2 term is 5 so

it gotta be something like 5x^2 + __ + __.

so...

in order to get that while maintaining the same zero's

you get

(5x-40)(x-9)=y

and there you go

or

it could also look like this

5(x-8)(x-9)=y

5(x - 8)(x - 9) = 5x^2 - 85x + 360

It is -b2 + or - the square root of 4 ac over 2a.