Answer:
the answer is four
The solution is in the picture above please mark me brainliest :)
Since you're only interested in x, you can use the first equation to write an expression for y that can be substituted into the second equation.
.. y = k -x
.. 2x +3(k -x) = k +1
.. -x +3k = k +1 . . . . . collect terms
.. 2k -1 -x = 0 . . . . . . subtract k+1
.. 2k -1 = x . . . . . . . . .add x
The 3rd selection is appropriate.
20^2 - 16^2 = 144
[square root] 144= 12m
12m
We must find UNIQUE combinations because choosing a,b,c,d... is the same as d,c,b,a...etc. For this type of problem you use the "n choose k" formula...
n!/(k!(n-k)!), n=total number of choices available, k=number of choices made..
In this case:
20!/(10!(20-10)!)
20!/(10!*10!)
184756
