# Category Archives: Algebra

## How The Heck Do I Translate With Matrices?

Help! Help! Help! Math 911!

“I’ve got 3 points: A (–4, 1), B (– 2, 5) and C (0, 2)
I’m supposed to translate each point 5 units right and 3 units down. What does that mean?”

“Glad you asked. It’s easy-peasy. You just add 5 to each x and subtract 3 from each y.
Solution: A’ = (1, -2) B’= (3, 2) C’ = (5, -1)

“Hold on a minute!” you scream! “I have to use Matrices! I don’t know where to start!”

“Oh, darn! In that case I’ll have to make you a video so I can draw matrices for you by hand. I don’t think you have the font that uses matrices. Shoot me an email and I’ll send it to you pronto! It’s really super simple once you see it.”

## I Can’t Do This Algebra Problem! Help!

“Come on!  You really want me to graph all those inequalities in that list when I can’t even graph a “regular” equation?”, gasps  the student.  Say it’s not so!!!

Teacher says, “It’s true alright.  It’s called a ‘system of inequalities’ and not only do I want you to graph them, I want you to graph them on the same graph!’

“On top of each other?” says the now panicking student.

“Yes.  Then I want you to look at the area you have shaded (you did shade didn’t you?).  Then find each vertex of the enclosed region.”

y>-1/2x+1

y<-3x+5

y<2x+2

Problems are taken from Advanced Math Concepts by Glencoe.

Solution:     The three vertices are:  (.6,  3.2)        (-.4,  1.2)       (1.6,   .2)

If you just ‘don’t get it’ and need a quick video demo, just email me and let me know. No charge.