\begin{tabular}{|c|c|}
\hline[tex]$x$[/tex] & [tex]$y$[/tex] \\
\hline 3 & 7 \\
\hline[tex]$k$[/tex] & 11 \\
\hline 12 & [tex]$n$[/tex] \\
\hline
\end{tabular}

The table above shows the coordinates of three points on a line in the [tex]$xy$[/tex]-plane, where [tex]$k$[/tex] and [tex]$n$[/tex] are constants. If the slope of the line is 2, what is the value of [tex]$k+n$[/tex]?



Answer :

To find the values of [tex]\(k\)[/tex] and [tex]\(n\)[/tex], and ultimately [tex]\(k + n\)[/tex], we will use the information provided about the points on the line and the given slope.

The slope of a line passing through two points [tex]\((x_1, y_1)\)[/tex] and [tex]\((x_2, y_2)\)[/tex] is calculated using the formula:

[tex]\[ \text{slope} = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]

Given the points [tex]\((3, 7)\)[/tex] and [tex]\((12, n)\)[/tex] with a slope of 2, we use the slope formula to find [tex]\(n\)[/tex]:

[tex]\[ 2 = \frac{n - 7}{12 - 3} \][/tex]

Simplify the denominator:

[tex]\[ 2 = \frac{n - 7}{9} \][/tex]

To solve for [tex]\(n\)[/tex], multiply both sides by 9:

[tex]\[ 2 \times 9 = n - 7 \implies 18 = n - 7 \][/tex]

Add 7 to both sides:

[tex]\[ n = 18 + 7 \implies n = 25 \][/tex]

Now, let's find the value of [tex]\(k\)[/tex]. Given the points [tex]\((3, 7)\)[/tex] and [tex]\((k, 11)\)[/tex] with the same slope of 2, we use the slope formula again:

[tex]\[ 2 = \frac{11 - 7}{k - 3} \][/tex]

Simplify the numerator:

[tex]\[ 2 = \frac{4}{k - 3} \][/tex]

To solve for [tex]\(k\)[/tex], multiply both sides by [tex]\((k - 3)\)[/tex]:

[tex]\[ 2(k - 3) = 4 \][/tex]

Distribute the 2:

[tex]\[ 2k - 6 = 4 \][/tex]

Add 6 to both sides:

[tex]\[ 2k = 10 \][/tex]

Divide by 2:

[tex]\[ k = 5 \][/tex]

Now that we have [tex]\(k = 5\)[/tex] and [tex]\(n = 25\)[/tex], we find [tex]\(k + n\)[/tex]:

[tex]\[ k + n = 5 + 25 = 30 \][/tex]

Therefore, the value of [tex]\(k + n\)[/tex] is [tex]\(\boxed{30}\)[/tex].