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Find slope given 2 points
Write equation given 2 points
Find y-intercept given slope and point
Find x-intercept given 2 points
Find x-intercept given y-intercept and slope
A line passes through the points (
21
,
-20
) and (
35
,
-24
). What is the x-intercept of the line?
-49
28
14
91
Skip
Hint
Can you answer 10 correctly?
Given points (21, -20) and (35, -24), the x-intercept is
?
The equation of a straight line in slope-intercept form is y = mx + b
b
is the y-intercept, which is where the line cross the y-axis (meaning x=0)
m
is the slope of the line, which tells you how steep the line is
For example, if you are given two points: (1,3) and (4,−3)
Find the slope using the equation of (y2 - y1) / (x2 - x1), so (-3 - 3) / (4 - 1), -6/3 = -2
Set the equation of the line to y = -2x + b
Plug in one of the points into the equation to find the y-intercept, so 3 = -2 x 1 + b, 3 = -2 + b, b = 5
To find x-intercept, set y=0 and solve for x, so 0 = -2x + 5, 2x = 5, x = 5/2
