Review: Writing Linear Equations in Slope Intercept Form

Review: Writing Linear Equations in Slope Intercept Form

What do you need to find to write an equation in slope-intercept form>

• First, find m (slope)

• Next, find b

Sometimes you are given both m (slope) and b (y-intercept)!

This is ready to go into slope-intercept form!

Answer

What happens if there is no b (y-intercept) given in the problem?

You will need to use slope and one point in y=mx+b to find the value of b (y-intercept)

To find b:

Use m and the x and y from the point in y=mx+b and solve for b

To solve you first perform the multiplication of m and x and then you use opposites to move it off that side to get b alone

Since m=11 and b=24 then equation of the line is y=11x+24

ANSWER FOR FINDING b

Sometimes no m (slope) or b (y-intercept) are given so we have to find both

To find m (slope):

If you are given two points then you must use the slope formula

Once you find the m (slope) you can then find the b (y-intercept)

Same steps as earlier using the slope you found and one of the points in y=mx+b

Steps:

• Find m using the slope formula (left)

• Find b using the m, x, and y in y=mx+b to get b alone (middle)

• Write your equation using the m and b you found (right)

Try Now:

Write the equation of a line that passes through the points (2,5) and (4,13)

Answer for slope

Answer for b

final answer

The final way to disguise slope is by stating that two lines are parallel or perpendicular

You need to know the relationship between their slopes to use the slope for your line

For perpendicular slopes you must:

1. Change the sign

..........AND

2. Flip the Fraction

To write equations for these special lines you follow the same steps as writing an equation given a point and slope