Learn how to find the equation of a straight line from a point and gradient!
Given Information:
Point: (x₁, y₁)
Gradient (m): ?
Line Equation Forms:
Point-slope form: y - y₁ = m(x - x₁)
Slope-intercept form: y = mx + c
Identify the x and y values for the point and the gradient:
Point:
x₁ = ?, y₁ = ?
Gradient:
m = ?
Use the formula: y - y₁ = m(x - x₁)
y - ? = ?(x - ?)
Expand the point-slope form by multiplying out the brackets:
y - ? = ?(x - ?)
y - ? = ?x - ?
Rearrange the equation to get y on its own:
y - ? = ?x - ?
y = ?x - ? + ?
Convert from y = mx + c to ax + by + c = 0
From y = ?x + ?
Rearrange to get: ?x - y + ? = 0
The equation of the line is:
y - y₁ = m(x - x₁)
y = mx + c
ax + by + c = 0
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