Find the Coordinate(s) of A?

Question

Mind you, I mean coordinates on a number line, not a graph...

A = -5x and Z= 4+x

AZ= 16

Find X and the Coordinate(s) of A...

I found x to be 2, but my friend said that 3 works too

WHICH IS RIGHT!?!?

Answer 1

Both of you are wrong. If you plug in 2 or 3, into the equation, neither will produce AZ=16.

Here's how you solve it:

AZ=16
(-5x)*(4+x) = 16
-20x -5x^2 = 16
5x^2 + 20x +16 = 0

Then solve for x using the quadratic formula. If you do it correctly, you should get x = -2 plus/minus 0.4*sqrt(5). Note that there are two possible values for x, since you're dealing with a quadratic equation.

If you round things, the two possible x-values are -1.11 and -2.89.
As for A, it's simply -5 times your x-value.

Did you perhaps have a typo in your problem? Given the ugliness of the answer and the fact that both of you got it wrong, I wouldn't be surprised if it turns out that you had a typo and both of you got correct answers for the actual problem. Anyway, if you did have a typo, the method I used above should help you solve the real problem too.

Answer 2

Are you sure you wrote the problem correctly? Neither 2 or 3 seem to work.