What do you call this kind of problem and how do you get the answer?

Question

W___X_____Y_______Z

On segment WZ above, if WY=21, XZ=26, and YZ is twice WX, what is the value of XY?
Please EXPLAIN to me how to get the answer

Answer 1

Just looking at it, WY = WX + XY since WY is made of the two pieces WX and XY.

And XZ = XY + YZ.



Let's see what else they're telling you.

"WY=21"

21 = WX + XY



"XZ=26"

26 = XY + YZ



"and YZ is twice WX"

This equation becomes 26 = XY + 2WX

And the other equation is 21 = XY + WX



That's two equations for two unknowns, XY and WX. Solve with standard simultaneous equation methods.



Edit: Actually you don't have to do a lot of algebra. If 21 = XY + WX and 26 = XY + WX + WX, then it's pretty obvious that WX is 26 - 21 = 5. And that tells you what XY is.

Answer 2

WX = a, XY = b, YZ = c

a+b = 21

c+b = 26

c = 2a

c-a = 5

2a-a = 5

a = 5

b = 16

c = 10

WX = 5

Answer 3

OMG! i have NO idea, what the hell? <_> OMG goodluck girl, man thts alot of hard sh!t