Question

I need someone to explain finding zeros of a function... I dont get it >.<
Helllppp.....Solve the equation: x2 - 10x + 25 = 16.

Answer 1

We have the equation
\[x^2-10x+25=16\]
Let's simplify this, then we'll find the zeros.
Could you subtract 16 from both the sides and write what would you get? @ginlynn17

Answer 2

x^2 - 10x+ 25- 16 ?

Answer 3

oh wait. x^2-10x+25-16=0

Answer 4

right ,
\[x^2-10x+25-16=0\]
or
\[x^2-10x+9=0\]
We could solve this in two ways, using quadratic formula or by factoring.
Which one do you want?

Answer 5

which ones easier? :D

Answer 6

Which one you are supposed to use? :P

Answer 7

It doesn't matter xD ... Can you explain factoring to me in like more detail? I haven't used factoring since like 8th grade .-.

Answer 8

Cool :)

Answer 9

\[x^2-10x+9=0\]
Standard quadratic equation is
\[ax^2+bx+c=0\]
Can you compare with our equation and tell what's the value of a. b and c?

Answer 10

The value of a is 1, b is -10, and c is 9

Answer 11

Good :)
Now find the product of a and c
\[a\times c\ ??\]

Answer 12

It's 9

Answer 13

Right :)
Now you need to find the factors of 9, such that their sum is b which is -10
Can you try>?

Answer 14

-9 and -1 ?

Answer 15

That's great :)

Answer 16

Now we write -10 x as -9x-x
\[x^2-9x-x+9=0\]
Now let's start taking common factors out
\[x(x-9)-x+9=0\]
Do you get this step?

Answer 17

@ginlynn17 ???

Answer 18

yeah i get the step

Answer 19

Now I'll take out -1 from the other two terms
\[x(x-9)-1(x-9)=0\]
Let's take out (x-9) from both the terms
\[(x-9)(x-1)=0\]
Do you get this?

Answer 20

yeah

Answer 21

So, we're done either x-9=0 or x-1=0
so
\[x=1, 9\]
voila !

Answer 22

Wait so instead of doing the work that you just did, could you just say (x-9)(x-1)=0 after you find the factors?

Answer 23

And thank you so much :)
You're good at explaining it. <3

Answer 24

yes :)

Answer 25

Welcome :)