Can anyone help me with these chemistry and one geometry question

CHEMISTRY: TRUE OR FALSE?

An element is considered a "pure substance", but a compound is not.

A compound is composed of 2 or more elements in a fixed ratio.

A solution has a uniform composition.

Compounds can be broken down into elements by physical means.

I answered these questions on a quiz (I answered 1. True, 2. False, 3. False, 4. True) and got them all wrong. I don't understand why though?

GEOMETRY:
T is the midpoint of AB. If T (-2, 1) and A (-5, 6), find the coordinates of B. I just have no idea how to do this so could you either show me how to do this one or do a different example and explain the steps?

For the geometry question do the midpoint formula which is (X1+X2/2, Y1+Y2/2) the -2 is the X1 and the X2 is the 1 and the -5 is the y1 and the y2 is the 6 just set them up as they are in the formula nd u will get ur answer

the answer for your geometry question is-
use midpoint formula...
let co-ordinates of A be(x1,y1)=(-5,6)
let co-ordinates of B be(x2,y2)
let co-ordinates of T be(x,y)=(-2,1)
now by midpoint formula,
x=(x1+x2)/2 and y=(y1+y2)/2
therefore,
(-2)=((-5)+x2)/2 and 1=(6+y2)/2
therefore, solving this we get,
x2=1 and y2=(-4)
thus the co-ordinates of B(x2,y2)=(1,-4)

I'm sorry but i can't explain you those chemistry answers...srry...