Linear Equations in Two Variables Ms Zuniga IB
Linear Equations in Two Variables Ms. Zuniga IB Math Studies 1 Room F 239
I. Slope-Intercept Form l l l y = mx + c m: slope/gradient = rise/run = Δy/Δx c: y-intercept
Gradient l l l Positive Zero (horizontal) y=# l l l Negative undefined (vertical) x=#
Point-gradient Form l y – y 1 = m(x – x 1)
Standard Form: Ax + By + C = 0 l l There can be no fractions or decimals (A, B, and C are integers) A must be greater than 0 Must be set = 0 The GCF of A, B, and C = 1
Graphing l You should be able to graph: • Given 2 points (plot the points and connect • • with a line) Given 1 point and gradient (first plot point and from that point follow the gradient) In slope-gradient form (put a pt. on the y-axis where the y-int is located, then from that pt. follow the gradient)
Writing Equations l You should be able to write an equation: • Given the y-intercept and gradient (just plug • • the values into the equation y = mx + c) Given the gradient and 1 point (substitute values of y, m and x to solve for c which is the y-intercept. Then rewrite the equation as y=mx + c) Given 2 points (find gradient first, choose 1 pt. to substitute values of y, m, and x as discussed above)
Parallel and Perpendicular Lines l l Parallel lines have the same gradient Perpendicular lines have negative reciprocal gradients
- Slides: 8