If [tex]s(x) = 2 - x^2[/tex] and [tex]t(x) = 3x[/tex], which value is equivalent to [tex](s \circ t)(-7)[/tex]?

A. -439
B. -141
C. 153
D. 443



Answer :

To determine the value of [tex]\((s \circ i)(-7)\)[/tex], we need to understand the composition of functions, specifically how to compose [tex]\(s(x)\)[/tex] and [tex]\(i(x)\)[/tex]. Here, [tex]\(i(x)\)[/tex] is the identity function, which means:

[tex]\[ i(x) = x \][/tex]

The composition of [tex]\(s\)[/tex] and [tex]\(i\)[/tex] is denoted as [tex]\((s \circ i)(x)\)[/tex], which means [tex]\(s(i(x))\)[/tex]. Since [tex]\(i(x) = x\)[/tex], this simplifies to:

[tex]\[ (s \circ i)(x) = s(i(x)) = s(x) \][/tex]

Therefore, [tex]\((s \circ i)(x)\)[/tex] is equivalent to simply [tex]\(s(x)\)[/tex].

Given:

[tex]\[ s(x) = 2 - x^2 \][/tex]

we substitute [tex]\(x = -7\)[/tex] into the function [tex]\(s(x)\)[/tex]:

[tex]\[ s(-7) = 2 - (-7)^2 \][/tex]

First, calculate [tex]\((-7)^2\)[/tex]:

[tex]\[ (-7)^2 = 49 \][/tex]

Then, substitute this value back into the function:

[tex]\[ s(-7) = 2 - 49 \][/tex]

Perform the subtraction:

[tex]\[ s(-7) = 2 - 49 = -47 \][/tex]

Thus, the value of [tex]\((s \circ i)(-7)\)[/tex] is [tex]\(-47\)[/tex].

The correct answer is not listed among the given options, but based on the calculations, [tex]\((s \circ i)(-7)\)[/tex] is equivalent to [tex]\(-47\)[/tex].
The answer is A because you do -7x3 first then (x^2)=21^2=441 Then 2-(441) is equal to 2-441 which equals -439