Question

Am I right?


If r(x) = -4x - 1 and t(x) = 2x - 1, find (r + t)(7).

Is -16?

Answer 1

yes you are :D

Answer 2

Thank god!! James really did help me a lot!

Answer 3

:D:D

Answer 4

you see, you can do it yourself

Answer 5

If h(x) = x - 1 and j(x) = -4x, find h[j(5)].

Is -16 as well?

Answer 6

no this is -21

Answer 7

o-o;; But.. What did I do wrong then?

Answer 8

good, for one problem. Now the other.
========
If h(x) = x - 1 and j(x) = -4x, find h[j(5)].

Find first the value of j(5)

Answer 9

j(5) = .... what?

Answer 10

-20

Answer 11

Right. Hence

h(j(5)) = h(20) = ... what?

Answer 12

... You lost me there.

Answer 13

You want to find the value of h(j(5)). Now we know that j(5) = -20. Therefore

h( j(5) ) = h( -20 )

as we just substituted the value for j(5)

Answer 14

5(-20)= -100

Answer 15

No. The function h is defined as h(x) = x - 1.

Therefore h(-20) = -20 - 1 = ... what?

Answer 16

That's what I got wrong!! I thought it was:

h(5)= 5-1 = 4

But, it's h(5)= -20-1 = -21!!

Answer 17

h(x)**

Answer 18

h(5) indeed is equal to 5 - 1 =4.

But h(-20) = -20 - 1 = -21.

Now you are trying to find the value of h(j(5)). That is NOT equal to h(5). First you have to evaluate j(5).

Answer 19

In other words,
\[ h(j(5)) \neq h(5) \]
because \( j(5) \neq 5 \).

Instead, as j(x) = -4x
\[ j(5) = -4(5) = -20 \]

Answer 20

Therefore,
\[ h(j(5)) = h(-20) = -21 \]

Answer 21

Thank you again... But, now I need help doing the fractions.


If f(x) = x - 4 and g(x) = 1/2 x - 2, find f[g(-6)].

How do I do fractions in this?

Answer 22

Is
\[ g(x) = \frac{1}{2x - 2} \]
?

Answer 23

No.... It's one 2 on the bottom and the "x" is next to the line.

Answer 24

so, it's like (1/2) x-2....?

Answer 25

\[ g(x) = (x/2) - 2 \] ?

Answer 26

umm,.

Answer 27

this is the same as (1/2)x - 2.