Find the equation of the line through points (-3,6) and (10,12). Find the equation of the line through points (7, 3) and (-4,3) These two Im having a hard time with!

1 Answer | Add Yours

baxthum8's profile pic

baxthum8 | High School Teacher | (Level 3) Associate Educator

Posted on

To identify the equation given 2 points.  First find the slope.

slope = `(rise)/(run) = ((y_(2)-y_(1))/(x_(2)-x_(1)))`

` `

Slope = `(6 - 12)/(-3 -10) = -6/-13 = 6/13`

Substitute a given point for (x, y) in slope intercept form to find y-intercept.

slope-intercept form: `y = mx + b`

m = slope; b = y-intercept

using point (-3, 6):  `6 = 6/13(-3)+b`

`6 = -18/13 + b`

` ` `b = 96/13`

` `Slope-intercept form of equation: `y = 6/13x + 96/13`

Rewriting in standard form by multiplying by 13 gives us:

`6x - 13y = -96`

` `For second equation;

slope = `(3-3)/(7- -4) = 0/11 = 0`

Slope 0 means horizonal line.  Since both points are on y-axis we have the equation:

`y = 3.`

Final Solutions:

#1) 6x - 13y = -96

#2) y = 3

` `

` `

We’ve answered 318,994 questions. We can answer yours, too.

Ask a question