ACT Math 4.5 Coordinate Geometry

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

its slope will be negative.

Now back to our old friend y equals mx plus

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

y over x dance like this...

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

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

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

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

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

Which is answer C.