2
There are some missing terms. First of all, I assume that A, B, and C are collinear and that B is between A and C.If this is true then AC-AB=BC by the whole is the sum of its parts theorem.24-20=4Otherwise, all that can be said about BC is that it's length is between AC-AB = 4 and AC+AB = 44 units.
12
Assuming that AB and AC are straight lines, the answer depends on the angle between AB and AC. Depending on that, BC can have any value in the range (22, 46).
a/b=c/d =>ad=bc =>a =bc/d b =ad/c c =ad/b d =bc/a so if a+b=c+d is true => (bc/d)+(ad/c)=(ad/b)+(bc/a) => (bc2+ad2)/dc=(da2+cb2)/ab => ab(bc2+ad2)=dc(da2+cb2) and since ad=bc, => ab(adc+add) =dc(ada+adc) => abadc+abadd =dcada + dcadc => abadc-dcadc =dcada-abadd => (ab-dc)adc =(dc-ab)add ad cancels out => (ab-dc)c =(dc-ab)d => -(dc-ab)c =(dc-ab)d => -c = d so there's your answer :)
2
yes because ab plus bc is ac
Commutativity.
That depends on the value of CD and the perimeter of the quadrilateral out lined in the question
36
It could be a vector sum.
The answer depends entirely on what AB, BC and AC are. And since you have not bothered to share that crucial bit of information, I cannot provide a more useful answer.
12
5
4.9
6.2
AB + BC = AC The sum of the parts equals a whole :]