X and Y Intercepts Standard Form Finding the

X and Y Intercepts & Standard Form Finding the X and Y intercepts from the Standard Form of an equation Ax + By =C Example: 3 x + 2 y = -6 X = -2 Y = -3 X – Intercept Y - Intercept 3 x + 2(0) = -6 3 x = -6 3 3 X = -2 3(0) + 2 y = -6 2 2 Y = -3

Slope Formula Finding the slope of a line when given two points on the same line. Example: m = (2, -1) & (3, 2) y 2 – y 1 X 2 – X 1 (2, -1) & (3, 2) X 1 , y 1 X 2 , Y 2 Step 2 - Plug the x m = 2 – (-1) and y values into 3 -2 Step 1 Label the points the formula Step 3 - Simplify m=3 1

Slope-Intercept Form An equation is in slope-intercept form when it is written as y = mx + b Example: a line has a slope of -4 and a y-intercept of 3. Write an equation in slope-intercept form Y = mx + b Slope y-intercept Substitute the given values for m and b. Y = -4 x + 3

Point-Slope Form You can graph a line if you know the slope and any point on the line. You can also write the equation of that line using point-slope form. Example: Write an equation in pointslope form for the line with slope 2 that contains the point (3, 1). Y – y 1 = m(x – x 1) slope The given point (x 1, y 1) Y – 1 = 2(x – 3) substitute 2 for m, 3 for x and 1 for y.

Rise Run Finding the slope of a line using rise over run Example: Find the slope of the line using rise for a line with run a slope of 2/3 RISE means how many units you move up or down or a change in the y values RUN means how far left or right you move or a change in the x values Step 1 - Find 2 “good” points Step 2 – create a right angle between the 2 points Step 3 – count and record the rise and the run