Question

Given f(x)=-x^2+2x, find f(-3).

Answer 1

Help?

Answer 2

f(-3) means x=-3
so substitute all x's for -3

Answer 3

So, f(-3)=-3^2+2(-4) ?

Answer 4

(-3)**

Answer 5

yes right remember coefficient is also negative so \[\huge\rm -(-3)^2+2(-3)\] now solve

Answer 6

3?

Answer 7

hmm no (-3)^2 =?

Answer 8

-6?

Answer 9

(-3)^2 is same as -3 times -3

Answer 10

9.

Answer 11

yes right so-(9)+2(-3) = ?

Answer 12

I got -15.

Answer 13

right

Answer 14

Would that be my final answer?

Answer 15

yes

Answer 16

Okay, would you mind helping me with just one more?

Answer 17

i'll try

Answer 18

If f(x)=x-3 and g(x)=2x-4, find (f+g)(x).

Answer 19

I tried working this one out and got 3x-7. Which I don't think is right.

Answer 20

just one question how did you get 3x :=)

Answer 21

I have no idea honestly. Haha

Answer 22

so how did you get 3x-7 ?

Answer 23

At the end how it has f+g and then x. I think that's how I got the x. Can you help?

Answer 24

(f+g)(x) means add both function f(x) and g(x) so
f(x) + g(x)

Answer 25

so replace f(X) with x-3 and f(x) with 2x-4
and then combine like terms
(x-3)+(2x-4)

Answer 26

Wouldn't you add the x to 2x and it becomes 3x?

Answer 27

yes right that's what i was asking

Answer 28

good job!

Answer 29

Thank you, so now the -3 and -4¿

Answer 30

?

Answer 31

yes right -3-4 are like terms

Answer 32

Would it be -7?

Answer 33

Ohh, would my answer actually be 3x-7?

Answer 34

yes right

Answer 35

Thank you so much for the help!

Answer 36

yw :=)