Question

Given the function f(x) = x^2 and k = –1, which of the following represents a function opening downward?
f(x) + k
kf(x)
f(x + k)
f(kx)

Answer 1

@sleepyhead314 @wolf1728

Answer 2

the coefficient of x would have to be negative in order for the function to open downward

Answer 3

Figured I'd come here but sleepyhead seems to be ding quite well

Answer 4

since "k" is a negative number

I would assume that they would like for us to multiply "x" with "k" somehow

Answer 5

i was thinking it'd be B or D?

Answer 6

D means that you would replace "kx" into the equation for "x"
that would get you f(kx) = (-1x)^2
^^ since this is squared, it would come out as a Positive
so that cannot be right

Answer 7

i don't know what it would be...

Answer 8

@sleepyhead314

Answer 9

since it cannot be D

then your other guess may be correct ;)

Answer 10

would it be k(fx)

Answer 11

yes ^

Answer 12

although the formatting is a bit confusing .-.

Answer 13

k = -1 f(x) = x^2 then
k(fx) = -x^2

Answer 14

so it would be B??:-)

Answer 15

I think it is B

Answer 16

mhmmm

Answer 17

yes as sleepyhead said the formatting is weird

Answer 18

thank you both! I will have one more question up and then done!

Answer 19

Okay, I'll stay here