Slide 1

ON TARGET EQUATIONS OF LINES

Slide 2

ON TARGET Given the slope and y-intercept. Use slope-intercept formula. Substitute the slope for m. Substitute the y-intercept for b. Ex. Write the equation of a line that has a y-intercept of -3 and a slope of .

Slide 3

ON TARGET Given the slope and a point. Use point-slope formula. Substitute the slope for m. Substitute the point for (x 1, y 1 ). Ex. Write the equation of a line that has a slope of 2 and passes through the point (-1, -3).

Slide 4

ON TARGET Given two points. Use the slope formula. Find the slope. Use point-slope formula. Substitute the slope for m. Substitute one of the given points for (x 1, y 1 ). Ex. Write the equation of a line passes through the points (0, -3) and (4, 5).

Slide 5

ON TARGET Vertical Lines Have an undefined slope. Equation: x = # Domain is a single x-value. Range is all real numbers. Example x = 2 D: {2}, R: {all real numbers}

Slide 7

ON TARGET x-intercept Point where a line crosses the x- axis. (#, 0) Find by setting y = 0 and solving for x.

Slide 8

ON TARGET y-intercept Point where a line crosses the y- axis. (0, #) Find by setting x = 0 and solving for y.

Slide 9

ON TARGET Describing a graph Describe a graph of a linear equation using the slope and y- intercept. First write the equation in slope- intercept form. Ex. 3x + y = 4 y = -3x + 4 The graph has a slope of -3 and a y-intercept of 4.

Slide 10

ON TARGET Parallel Lines Same slope Different y-intercepts Parallel lines will NEVER intersect. Ex. y = -3x + 4 and y = -3x 3

Slide 11

ON TARGET Perpendicular Lines Slopes are opposite reciprocals Different y-intercepts Perpendicular lines form 90 degree angles at their intersection. Ex. y = -3x + 4 and y = (1/3)x 3