Verified Answer :

find the slope
(y2-y1)/(x2-x1)=slope
(15-7)/(5-1)=8/4=2
slope is 2

either 1st or 3rd
function notaiton seems to be f(x)

3rd otpion is answer
f(x)=2x+5

Answer:

Option C is correct.

The equation of line is , f(x)=2x+5

Step-by-step explanation:

Point slope intercept form: For any two points \((x_1, y_1)\) and \((x_2, y_2)\)  then,

the general form of the equation of line is given by;

\(y-y_1=m(x-x_1)\);  where m is the slope given by:

\(m=\frac{y_2-y_1}{x_2-x_1}\)

Consider the given points;

(1, 7) and (5 , 15)

First calculate the slope (m);

\(m=\frac{y_2-y_1}{x_2-x_1} =\frac{15-7}{5-1} =\frac{8}{4} =2\)

Therefore, slope of the line, m=2

Then, the equation of line is:

\(y-y_1=m(x-x_1)\)

Substitute the value of m=2 and (1, 7) above we get;

\(y-7=2(x-1)\)

or

\(y-7=2x-2\)

Add 7 to both sides of an equation we get;

\(y-7+7=2x-2+7\)

Simplify:

\(y=2x+5\)

using function notation i.e, y =f(x)

then, we have f(x) = 2x+5

therefore, the equation of line that passes through the point (1, 7) and (5, 15)  is ; f(x)=2x+5