Question

f(x)={x^2+2x x<=-1}
{x+8 x>-1}
find f(-4)
f(-1)

Answer 1

let's find f(-4) first

Answer 2

f(-4) means find f(x) when x = -4

Answer 3

I solved f(6) and got 14.. but got the others wrong.

Answer 4

what did you get for f(6)?

Answer 5

my answer is 14 and I got it right.

Answer 6

keep in mind that when x = -4, we're looking at the first piece (since x <= -1 here)

Answer 7

f(6) = 14 is correct

Answer 8

so I just plug in right?

Answer 9

because when x = 6, which is greater than -1, we look at the corresponding piece x+8

Answer 10

but when x = -4, we look at the first piece since f(x) = x^2 + 2x when x <= -1

Answer 11

-24?

Answer 12

f(x) = x^2 + 2x

f(-4) = (-4)^2 + 2(-4)

f(-4) = 16 + 2(-4) <<--- This is where you made your mistake

f(-4) = 16 - 8

f(-4) = 8

Answer 13

(-4)^2 = 16 and NOT (-4)^2 = -16

Answer 14

gahh, okay.

Answer 15

that's ok, it gets a lot of people

Answer 16

thank you!

Answer 17

you're welcome