I have 2 equations... f[1] := x[2]+x[3]+x[5]+x[6]=16; and f[2] := x[1]+x[2]-x[3]+x[4]+3*x[6]+x[7]=28; 

Is there a method that will allow me to count the number of equations?

Is there a method to display the indeterminants or variables which are in the equations i.e x[1],x[2],x[3],x[4],x[5],x[6],x[7]?

Is there a method to find the maximum indeterminant or variable from both the equations i.e x[7]?

I have a list c:= [1,2] and i would like to add a new element to this list so that the result is c:=[1,2,3], how would this be done?

And if this can be done is there a way to specify where in the list the element is added to?

Thanks in advance for any help. 

I have a vector column XbIndets := (6,7,8) and I would like to gain the 3rd element of this i.e 8. I know it is possible using row function when using a matrix but am unsure how this is done when using a vector. 

Any help is much appreciated

I have two vectors ( A=(1,2,3,4,5,6,7,8), B=(2,7,8) ) and I would like to compare them to see if the elements in B are also in A, and then if they are I would like to remove them from A so I would be left with the following A=(1,3,4,5,6). Is this possible and if so how?

Any help is much appreciated

I am new to using maple and I have an equation (z:= 7*x[1]+11*x[3]-10*x[4]+26*x[6]) which i would like to turn into a sequence of coefficient of x's i.e (7,0,11,-10,0,26). How would I go about doing this?