# Graphing Equations & Equations of Lines GRAPHING EQUATIONS & EQUATIONS OF LINES Lesson 13.1 & 13.2 STRATEGIES TO GRAPH A LINE Make a table. Special lines Vertical lines Horizontal Lines Intercepts (x, 0) & (0, y) Slope-intercept form

MAKE A TABLE & GRAPH 2X 4Y = 10 x y -1 -3 0 1 -5/2 -2 2

-3/2 SPECIAL LINES: GRAPH Y = 4 & X = -2 y = 4 is a horizontal line where all the y values are 4. x = -2 is a vertical line where all of the x values are -2. INTERCEPTS FIND THE X- AND Y- INTERCEPTS FOR THE LINE 2X 5Y = 10, THEN GRAPH. X intercept:

What is x when y is zero? 2x 5(0) = 10 x = 5 . (5, 0) Y-intercept: What is y when x is zero? 2(0) 5y = 10 y = -2 (0, -2) USE SLOPE-INTERCEPT FORM TO GRAPH THE LINE Y = 2X - 5. y = mx + b y

& x are any point (x, y) that line on the line. m is the slope b is the y-intercept (0, b) In the equation y = 2x 5, m =2 b = (0, -5) Graph the y-intercept Graph the slope Connect the dots.

VARIOUS FORMS OF LINEAR EQUATIONS Slope-Intercept Form (y-form) y = mx + b Point-Slope Form y y1 = m(x x1)

m = slope and (x1, y1) is a known point Standard Form (General Form) Ax + By = C THINGS NOT TO FORGET ABOUT LINEAR EQUATIONS 1. 2.

3. 4. 5. Parallel Lines have the SAME slope but different y-intercepts. Perpendicular lines have slopes that are negative reciprocals. Vertical lines have a slope that is undefined. Horizontal lines have a slope of zero. Midpoint between two points is found using the formula: x1 + x2 , y1 + y2 2 2