Dividing by variable when solving algebraic equation

[Longhorn]

I'm teaching my 11th graders quadratic functions right now, they are not amused. Question: you have 100 meters of fence to fence in a rectangular area, but one of the sides doesn't need a fence because there's a wall already. So the question is, how long and wide do you choose your corral to maximize the area.

How most physics questions used to sound to me:

A ball is falling from 25m. The mass of the ball is 2kg. Calculate the exact time of the plane landing in Bangladesh if the sun is seen on the north side of the sky and the course of Euro is 2$.

[Whateverist]

I'd estimate 46?

[robvalue]

Lol

It was touch and go for a while, but I pulled through

[robvalue]

[Fireball]

Could I have an example?

Any equation where the constant is positive will do.

E.g. x^2 + 4

Let's test where it intersects the x axis:

x^2 + 4 = 0

=> x^2 = -4

therefore, x = 2i

Thanks! Next time, I'll pour more coffee down the inside of my neck before I ask a question. I taught algebra for a couple of years. My brain obviously had checked out for parts unknown while reading this thread.

[LastPoet]

I'm teaching my 11th graders quadratic functions  right now, they are not amused.  Question: you have 100 meters of fence to fence in a rectangular area, but one of the sides doesn't need a fence because there's a wall already. So the question is, how long and wide do you choose your corral to maximize the area.

How most physics questions used to sound to me:

A ball is falling from 25m. The mass of the ball is 2kg. Calculate the exact time of the plane landing in Bangladesh if the sun is seen on the north side of the sky and the course of Euro is 2$.

It is exactly 42.

[Kernel Sohcahtoa]

I know for all you math masters out there, this is basic stuff.

I'm far from a being a math master myself.  For me at least, I think math is cool and am interested in gaining a basic understanding of it.  That being said, I thought your post was pretty cool.  I've often found that when I'm struggling with a problem, it is due to my lack of familiarity with the basics, such as having an incomplete understanding of particular terms in definitions or being a bit rusty in fundamental algebra, trig, or calc concepts (etc.).  Furthermore, I've learned to value the instances where I have the humility to crack open the books, engage in research, or pick another person's brain: this helps me avoid the trap of using the same problematic thinking, which got me confused in the first place.  

P.S. Thanks for the cool thread and good luck with your math endeavors, sir.

[Jesster]

I have a secret to solve any algebra problem. Multiply both sides by zero.

0 = 0

Done.

[GrandizerII]

I have a secret to solve any algebra problem. Multiply both sides by zero.

0 = 0

Done.

But then what would be the solution?

[Jesster]

I have a secret to solve any algebra problem. Multiply both sides by zero.

0 = 0

Done.

But then what would be the solution?

ZERO

Sheesh. It's like you weren't even listening.