Writing Equations from graphs and graphing equations

y = x - 5 y-intercept slope 1st find y-intercept – where the line crosses the Y axis 2nd find Slope – angle of the line

y = x - 5 1st - y-intercept – where the line crosses the Y axis

y = x - 5 Slope is the angle of the line. You can think slope Rise – how far you “rise” – go up/down Run – how far you “run” across the grid

y = x - 5 Rise = 2 Run = 3

Hehe 

y = 2x + 6

Can go in either order – over first, then up/down or up/down the over y = 2x + 6 slope = remember 2 = If you can’t go over (right) and up – do the opposite = over left and down

One more!!!

y = -3x + 2

y = -3x + 2 -3 = which means instead of right then up, it’s right then DOWN

Given a graph – make an equation 1. Find y-intercept 2. Find slope =

Given a graph – make an equation 1. Find y-intercept b = 2

Given a graph – make an equation 2. Find slope = Run = 2 Rise = -1 Negative because it’s down =

Put it together y = mx + b m = b = 2 y = x + 2

Y-intercept = -4 = m y = mx + b y = 3x -4 Find the equation for the graph: Y-intercept = -4 Rise = 3 Run = 1 = m y = mx + b y = 3x -4