Finding an Equation of a Line

Finding an Equation of a Line

Multiple Choice

m represents the ____________

• y-intercept

• x value

• y value

• slope

Multiple Choice

The y intercept is ___ in

y=mx+b

• b

• x

• m

• y

Multiple Choice

The y intercept is where the line passes through the _________.

• x axis

• y axis

• origin

• sun

From yesterdays notes......

We can find an equation of a line given the slope and a point.

Do you remember how?

Poll

Do you remember how?

• yes!

• I think so?

• No idea!

• I did not watch yesterdays video.

If you do not remember.

• Find the value of x and y from the coordinate.

• Remember a coordinate is (x,y).

• Use the given slope which is m.

• Substitute in x, y, and m into y=mx+b

• solve for b

• Write the equation in y=mx+b form with the given value for the slope (m) and the value for the y-intercept you found. (b)

Example: m = 1/3 , (3,2)

• Find the value of x and y from the coordinate. x = 3, y=2

• Remember a coordinate is (x,y).

• Use the slope which is m. m=1/3

• Substitute in x, y, and m into y=mx+b 2=(1/3)(3) + b

• Solve fo b. b = 1

• Write the equation in y=mx+b form with the given value for the slope (m) and the value for the y-intercept you found. (b)

• y=mx + b y=1/3x + 1

So if given m = 1/3 , (3,2) and asked to find the equation the equation would be.......

y=1/3x + 1

If you were incorrect.....

m = -4; (-1,2)

x = -1, y = 2, m = -4

y = mx + b

2 = -1(-4) + b

2 = 4 + b

-4 -4

-2 = b

So using m and b

y = -4x - 2