Suppose that the functions [tex]r[/tex] and [tex]s[/tex] are defined for all real numbers [tex]x[/tex] as follows:

[tex]\[
\begin{array}{l}
r(x) = 2x \\
s(x) = 4x^2
\end{array}
\][/tex]

Write the expressions for [tex](r - s)(x)[/tex] and [tex](r \cdot s)(x)[/tex], and evaluate [tex](r + s)(-2)[/tex].

[tex]\[
\begin{aligned}
(r - s)(x) & = \square \\
(r \cdot s)(x) & = \square \\
(r + s)(-2) & = \square
\end{aligned}
\][/tex]



Answer :

To solve the problem, let's first define the given functions:

[tex]\[ r(x) = 2x \][/tex]
[tex]\[ s(x) = 4x^2 \][/tex]

### 1. Expression for [tex]\((r - s)(x)\)[/tex]:

[tex]\[ (r - s)(x) = r(x) - s(x) \][/tex]
[tex]\[ (r - s)(x) = 2x - 4x^2 \][/tex]

So, the expression for [tex]\((r - s)(x)\)[/tex] is:

[tex]\[ (r - s)(x) = 2x - 4x^2 \][/tex]

### 2. Expression for [tex]\((r \cdot s)(x)\)[/tex]:

[tex]\[ (r \cdot s)(x) = r(x) \cdot s(x) \][/tex]
[tex]\[ (r \cdot s)(x) = (2x) \cdot (4x^2) \][/tex]
[tex]\[ (r \cdot s)(x) = 8x^3 \][/tex]

So, the expression for [tex]\((r \cdot s)(x)\)[/tex] is:

[tex]\[ (r \cdot s)(x) = 8x^3 \][/tex]

### 3. Evaluation of [tex]\((r + s)(-2)\)[/tex]:

[tex]\[ (r + s)(x) = r(x) + s(x) \][/tex]

First, let's evaluate [tex]\(r(-2)\)[/tex]:

[tex]\[ r(-2) = 2 \cdot (-2) = -4 \][/tex]

Now, let's evaluate [tex]\(s(-2)\)[/tex]:

[tex]\[ s(-2) = 4 \cdot (-2)^2 = 4 \cdot 4 = 16 \][/tex]

Now, let's find [tex]\((r + s)(-2)\)[/tex]:

[tex]\[ (r + s)(-2) = r(-2) + s(-2) \][/tex]
[tex]\[ (r + s)(-2) = -4 + 16 = 12 \][/tex]

So, [tex]\((r + s)(-2) = 12\)[/tex].

Putting it all together:

[tex]\[ \begin{aligned} (r - s)(x) &= 2x - 4x^2 \\ (r \cdot s)(x) &= 8x^3 \\ (r + s)(-2) &= 12 \end{aligned} \][/tex]