Line [tex]$JK$[/tex] passes through points [tex]$J(-3, 11)$[/tex] and [tex][tex]$K(1, -3)$[/tex][/tex]. What is the equation of line [tex]$JK$[/tex] in standard form?

A. [tex]$7x + 2y = -1$[/tex]
B. [tex][tex]$7x + 2y = 1$[/tex][/tex]
C. [tex]$14x + 4y = -1$[/tex]
D. [tex]$14x + 4y = 1$[/tex]



Answer :

To find the equation of the line passing through points [tex]\( J(-3, 11) \)[/tex] and [tex]\( K(1, -3) \)[/tex] in standard form, we need to go through several steps:

1. Calculate the slope (m) of the line:

The formula for the slope [tex]\( m \)[/tex] between two points [tex]\((x_1, y_1)\)[/tex] and [tex]\((x_2, y_2)\)[/tex] is:
[tex]\[ m = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]

Plugging in the coordinates of points [tex]\( J \)[/tex] and [tex]\( K \)[/tex]:
[tex]\[ m = \frac{-3 - 11}{1 - (-3)} \][/tex]
Simplify the subtraction and addition:
[tex]\[ m = \frac{-14}{4} = -3.5 \][/tex]

2. Calculate the y-intercept (b):

We use the point-slope form of the line equation [tex]\( y = mx + b \)[/tex]. Choose point [tex]\( J \)[/tex] for the calculation:
[tex]\[ 11 = (-3.5)(-3) + b \][/tex]
Simplify and solve for [tex]\( b \)[/tex]:
[tex]\[ 11 = 10.5 + b \\ b = 11 - 10.5 \\ b = 0.5 \][/tex]

So the equation of the line in slope-intercept form is:
[tex]\[ y = -3.5x + 0.5 \][/tex]

3. Convert the equation to standard form [tex]\( Ax + By = C \)[/tex]:

Start with:
[tex]\[ y = -3.5x + 0.5 \][/tex]
To eliminate the decimal in the slope, multiply every term by 2:
[tex]\[ 2y = -7x + 1 \][/tex]
Rearrange to standard form:
[tex]\[ 7x + 2y = 1 \][/tex]

4. Compare the simplified standard form with the given options:

The given problem options are:
- [tex]\( 7x + 2y = -1 \)[/tex]
- [tex]\( 7x + 2y = 1 \)[/tex]
- [tex]\( 14x + 4y = -1 \)[/tex]
- [tex]\( 14x + 4y = 1 \)[/tex]

We can see that the correct standard form from our derivation is:
[tex]\[ 7x + 2y = 1 \][/tex]

Therefore, the correct equation of line [tex]\( JK \)[/tex] in standard form is:
[tex]\[ 7x + 2y = 1 \][/tex]