ACT Math 4.5 Coordinate Geometry

ACT Math: Coordinate Geometry Drill 4, Problem 5. What is the equation of the graph in the video?

ACT MathCoordinate Geometry
ACT MathematicsCoordinate Geometry
AlgebraCoordinates and Graphs
Coordinate GeometryGraphing equations
Graphs of points, lines, polynomials, and circles
The relations between equations and graphs
Foreign LanguageArabic Subtitled
Chinese Subtitled
Korean Subtitled
Spanish Subtitled
GeometryCoordinate Geometry
LanguageEnglish Language
Product TypeACT Math

Transcript

00:27

on the line are .5, 0 and 0, 2. And since the line slopes downward, we know

00:34

its slope will be negative.

00:36

Now back to our old friend y equals mx plus

00:38

b, the standard form of a line. We can get the slope m by doing the

00:43

y over x dance like this...

00:45

and we get y2 minus y1 over x2 minus x1...

00:48

...or 2 minus 0 over 0 minus .5... ...which equals negative 2 divided by a half

00:54

or... negative 4. So we have y equals negative 4 times x plus

00:58

b...and we can just plug in some points to get b. Let's try the 2nd point - zero, 2

01:05

We have 2 equals negative 4 times 0 plus b or... 2 equals... b.

01:10

Which is answer C.