Question

help do i plugin for S and T?

Answer 1

@Michele_Laino

Answer 2

by definition, we have
(s+t)(x)=s(x)+t(x), so what do you get?

Answer 3

0

Answer 4

if you solve for x we get 0 correct @Michele_Laino

Answer 5

you have to replace s(x) with x+4
and t(x) with 3x+2

Answer 6

so s(x) would be 4(x)

Answer 7

and t(x) would 3(2)

Answer 8

4+3(2)=4(2)+3(2)

Answer 9

hint:
s(x)+t(x)=x+4+3x+2=...?

Answer 10

so it's x+4+3x+2 then what do i plug in for (s+t)

Answer 11

you have to plug in the subsequent expression:
s(x)+t(x)=x+4+3x+2= 4x+6

Answer 12

(s+t)(x)=4x+6

Answer 13

ok but where did 4x+6 come from

Answer 14

since I have computed this sum:
x+4 + 3x+ 2= 4x+6

Answer 15

ok got that part so now we (s+t) (x)=4x+6 correct

Answer 16

correct!

Answer 17

so i need to solve that correct

Answer 18

next we have to write the expression for the function (s-t)(x)
In order to that, we have:
(s-t)(x)=s(x)-t(x)=(x+4)-(3x+2)=...?

Answer 19

ok i see we added the 2 equations together for (s+t)(x) but wouldn't we do s*t next?

Answer 20

hint:
(s*t)(x)= s(x)*t(x)= (x+4)*(3x+2)=...?

Answer 21

13x+2

Answer 22

no, you have to applu the foil method

Answer 23

apply*

Answer 24

what do you get?

Answer 25

oh ok so 3x2+14x+8

Answer 26

3x^2**

Answer 27

and for s-t(-1) i got 2(2x+3) is that right

Answer 28

no, I think taht it is wrong

Answer 29

that*

Answer 30

which one the answer i got for s*t or s-t(-1)

Answer 31

ok i subtracted instead of factoring for the last one i got 4x+6

Answer 32

is that right @Michele_Laino

Answer 33

I got this:
s(x)-t(x)=x+4-3x-2=-2x+2

Answer 34

but its 3x+2 not 3x-2 so wouldn't it be x+4-3x+2?

Answer 35

no, since we have to to this subtraction:
(x+4)-(3x+2)=
=x+4 - 3x -2

Answer 36

so its actually -2x+2

Answer 37

wait your forgetting (-1)

Answer 38

in that case we get -2x+6

Answer 39

no, since s(x)=x+4
and t(x)=3x+2
so when we compute the substraction we have to distribute the minus sign, like this:
(x+4)-(3x+2)=
=x+4 - 3x -2 =-2x+2

Answer 40

ok ok i got it

Answer 41

thanks man

Answer 42

now you have to substitute x=-1, so we have:
(s-t)(-1)=-2*(-1)+2=...?
what do you get?

Answer 43

\[\left( {s - t} \right)\left( { - 1} \right) = \left\{ { - 2 \times \left( { - 1} \right)} \right\} + 2 = ...?\]

Answer 44

t=s+4x+2

Answer 45

it is wrong, since we hav:
\[\left( {s - t} \right)\left( { - 1} \right) = \left\{ { - 2 \times \left( { - 1} \right)} \right\} + 2 = 2 + 2 = ...?\]

Answer 46

have*

Answer 47

im lost

Answer 48

wait is it -3/4

Answer 49

we can write this:
\[\begin{gathered}
\left( {s - t} \right)\left( x \right) = - 2x + 2 \hfill \\
\hfill \\
\left( {s - t} \right)\left( { - 1} \right) = - 2 \times \left( { - 1} \right) + 2 = 2 + 2 = 4 \hfill \\
\left( {s - t} \right)\left( { - 1} \right) = 4 \hfill \\
\end{gathered} \]

Answer 50

ah ok srry i was looking at it differently

Answer 51

so its 4

Answer 52

that's right!

Answer 53

ok! you answers are right!

Answer 54

ok I'm going to open a new thing so you can check my others if I'm wrong please

Answer 55

ok!