Polynomial

[mathxyz]

Polynomial

Question : (g-h)(10)

NOTE:
F(x)=x^2-9

g(x)=2x

h(x)=x-3

My Work:


(g-h) +10

Simplify Multiplication on the left side: + 10g - 10h
Substitute for the letter g on the left side: + 10 *(+ 2x )- 10h

Substitute for the letter h on the left side:
+ 10 *(+ 2x )- 10 *(+ x - 3 )

Simplify Multiplication on the left side: + 20x - 10x + 30

Combine like terms on the left side: + 10x + 30

Subtract + 30 from each side: + 10x + 30 - 30 - 30

Divide each side by + 10 .

+ 10x =- 30

+ 10 + 10

+ x =- 3

Am I right?

 

[soroban]

Hello, mathxyz!

You're just starting "functions", right?
It seems that you don't understand the notation, though.


You are given one function: . f(x) = 4x - 3

. . f(2) means "Let x = 2 in the function".
. . So we have: . f(2) .= .4(2) - 3 .= .5
. . And: .f(-3) .= .4(-3) - 3 .= .-15


You are given two functions: .g(x) = 2x .and .h(x) = x - 3

. . Then g - h means: .g(x) - h(x) . . . subtract the two functions.
. . And we get a new function: . g - h .= .(2x) - (x - 3) .= .x + 3

. . If they want us to plug in x = 4, they will write: . (g - h)(4)

Question: . Find (g-h)(10)

Given: . g(x)=2x, . h(x) = x - 3

First find g - h

g - h .= .(2x) - (x - 3) .= .x + 3

Now, (g - h)(10) means "Let x = 10 in this function".
. . . So we have: . (g - h)(10) .= .10 + 3 .= .13

 

[mathxyz]

hey

Thanks a lot.