Find the equation of the line that passes through the points [tex]\((2,1)\)[/tex] and [tex]\((5,4)\)[/tex].

A. [tex]\( y = x + 1 \)[/tex]

B. [tex]\( y = -x - 1 \)[/tex]

C. [tex]\( y = x - 1 \)[/tex]

D. [tex]\( y = x + 3 \)[/tex]



Answer :

To find the equation of the line that passes through the points [tex]\((2, 1)\)[/tex] and [tex]\((5, 4)\)[/tex], we will:

1. Calculate the slope (m) of the line:
[tex]\[ m = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]
Here, [tex]\( (x_1, y_1) = (2, 1) \)[/tex] and [tex]\( (x_2, y_2) = (5, 4) \)[/tex].

Plugging in the coordinates:

[tex]\[ m = \frac{4 - 1}{5 - 2} = \frac{3}{3} = 1 \][/tex]

2. Use the point-slope form of the equation of a line to find the equation:
The point-slope form is given by:

[tex]\[ y - y_1 = m(x - x_1) \][/tex]

Substituting [tex]\( m = 1 \)[/tex], [tex]\( x_1 = 2 \)[/tex], and [tex]\( y_1 = 1 \)[/tex]:

[tex]\[ y - 1 = 1(x - 2) \][/tex]

3. Simplify the equation:
Distribute the slope and move the constants to one side:

[tex]\[ y - 1 = x - 2 \][/tex]

Add 1 to both sides:

[tex]\[ y = x - 2 + 1 \][/tex]

Simplify:

[tex]\[ y = x - 1 \][/tex]

So, the equation of the line passing through the points [tex]\((2, 1)\)[/tex] and [tex]\((5, 4)\)[/tex] is:

[tex]\( \boxed{y = x - 1} \)[/tex]

In the given options:

a. [tex]\(y = x + 1\)[/tex] \\
b. [tex]\(y = -x - 1\)[/tex] \\
c. [tex]\(y = x - 1\)[/tex] \\
d. [tex]\(y = x + 3\)[/tex]

The correct answer is [tex]\( \boxed{c} \)[/tex].