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Find the equation of the line joining the points (2,11) and (4,17)
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First, calculate the slope.
The formula for the slope of a straight line passing through two given points (,) and (,) is
m = .
Substitute the given data = 2, = 11, = 4, = 17 into the basic formula
m = = = 3.
Next, find an equation of the line having the slope 3 and passing through the given point (2,11).
An equation of a straight line in a coordinate plane which has the slope m and passes through the given point P = (a,b) is
y - b = m*(x-a).
Substitute here m = 3, a = 2, b = 11, and you will get
y - 11 = 3*(x-2).
It is the equation in the slope-point form.
If you want to have it in the slope-intercept form, transform it in this way
y = 3x - 6 + 11, or
y = 3x + 5.
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See the lesson
- Equation for a straight line in a coordinate plane passing through two given points
in this site.