WRITING A LINEAR EQUATION GIVEN THE SLOPE
AND Y-INTERCEPT
Use the equation y = mx + b
The slope is the m in the equation.
The b is the y-intercept in the equation.
The equation of your line should be in the form y = #x + #
where you have filled in for the missing #’s
Slope = 5 and the y-intercept = -3
y = 5x - 3
slope
y-intercept
WRITING A LINEAR EQUATION GIVEN A POINT
AND THE SLOPE.
Use the equation y = mx + b
The slope is your m in the equation.
The point is your x and y in y = mx + b.
The only part of the equation that you do not know is b, so you must
find it.
Substitute in x, y, and m into y = mx + b and solve for b.
After finding b, go back to y = mx + b and substitute in the value of b
and the slope.
(4,5), slope =
1
4
5 = (4) + b
5=1+b
-1 -1
4=b
1
4
Substitute in m and b
1
4
y= x+4
m
b
WRITING A LINEAR EQUATION WITH TWO
POINTS
Find the slope of the line with the slope equation
 − 
 − 
Find the b value by picking one of the given points and substituting x, y,
and b into y = mx + b.
Substitute m and b into y = mx + b
(-8, 84), (5, -46)
−−
+
= -10
Pick point
=m
-46 = -10(5) + b
-46 = -50 + b
+50 +50
4=b
Substitute in m and b
y = -10x + 4
Download

Writing linear equations