Question

how would you identify the x intercepts of f(x)=25-x^2? No graphing calculator allowed.

Answer 1

set 25-x^2=0

Answer 2

and then factor (x+5)(x-5)?

Answer 3

Take y=0 for finding x-intercepts.
0=25-x^2
Take x^2 to the other side,
x^2=25
Or x=5

Answer 4

yes

Answer 5

so \[x=\pm 5\]

Answer 6

\[x^2=25, x= \pm 5\]

Answer 7

Yes that's right.

Answer 8

thank you!

Answer 9

wait.. but it's a negative x..

Answer 10

There are 2 solutions, positive and negative 5

Answer 11

OH, you moved it to the other side, gotcha

Answer 12

yeah no need to factor that one, pretty easy :)

Answer 13

wasn't thinking straight, what a simple question that was.. hahah wow. -facepalm-

Answer 14

It happens, because of our awesome education systems we tend to make easy things difficult sometimes.