Select the correct answer.

Which equation shows a correct evaluation of [tex]\((m \circ n)(4)\)[/tex]?

[tex]\[
\begin{array}{l}
m(x)=4x-5 \\
n(x)=2x+11
\end{array}
\][/tex]

A. [tex]\((m \circ n)(4)=8(4)^2-6(4)-55\)[/tex] \\
B. [tex]\((m \circ n)(4)=8(4)^2-55\)[/tex] \\
C. [tex]\((m \circ n)(4)=8(4)^2+34(4)-55\)[/tex] \\
D. [tex]\((m \circ n)(4)=8(4)-55\)[/tex]



Answer :

To evaluate [tex]\((m \circ n)(4)\)[/tex], we must first determine the composition of the functions [tex]\( m \)[/tex] and [tex]\( n \)[/tex].

We are given:
[tex]\[ m(x) = 4x - 5 \][/tex]
[tex]\[ n(x) = 2x + 11 \][/tex]

The composition [tex]\((m \circ n)(x)\)[/tex] means substituting [tex]\( n(x) \)[/tex] into [tex]\( m(x) \)[/tex]. This can be written as:
[tex]\[ (m \circ n)(x) = m(n(x)) \][/tex]

Next, we substitute [tex]\( n(x) \)[/tex] into [tex]\( m(x) \)[/tex]:
[tex]\[ m(2x + 11) = 4(2x + 11) - 5 \][/tex]

Performing the multiplication and simplification, we get:
[tex]\[ m(2x + 11) = 4 \cdot 2x + 4 \cdot 11 - 5 \][/tex]
[tex]\[ m(2x + 11) = 8x + 44 - 5 \][/tex]
[tex]\[ m(2x + 11) = 8x + 39 \][/tex]

Now, to evaluate [tex]\((m \circ n)(4)\)[/tex], substitute [tex]\( x = 4 \)[/tex] in [tex]\( m(2x + 11) \)[/tex]:
[tex]\[ (m \circ n)(4) = 8(4) + 39 \][/tex]
[tex]\[ (m \circ n)(4) = 32 + 39 \][/tex]
[tex]\[ (m \circ n)(4) = 71 \][/tex]

We then compare this result with the given options to see if any match:

A. [tex]\((m n)(4) = 8(4)^2 - 6(4) - 55\)[/tex]

B. [tex]\((m n)(4) = 8(4)^2 - 55\)[/tex]

C. [tex]\((m n)(4) = 8(4)^2 + 34(4) - 55\)[/tex]

D. [tex]\((m n)(4) = 8(4) - 55\)[/tex]

Evaluating each:

Option A:
[tex]\[ 8(4)^2 - 6(4) - 55 = 8(16) - 24 - 55 = 128 - 79 = 49 \][/tex]

Option B:
[tex]\[ 8(4)^2 - 55 = 8(16) - 55 = 128 - 55 = 73 \][/tex]

Option C:
[tex]\[ 8(4)^2 + 34(4) - 55 = 8(16) + 136 - 55 = 128 + 136 - 55 = 264 - 55 = 209 \][/tex]

Option D:
[tex]\[ 8(4) - 55 = 32 - 55 = -23 \][/tex]

None of the provided options match the correct evaluation of 71. Therefore, the correct answer is:

[tex]\[ \boxed{\text{No correct option available}} \][/tex]