@JAMET  See code below. x, y, z are the barycentric coordinates of point M:

restart;
with(LinearAlgebra):
A:=<1,-3,0>: B:=<-2,1,1>: C:=<3,1,2>: M:=x*A+y*B+z*C:
{DotProduct(B-A,C-M)=0, DotProduct(C-A,B-M)=0, x+y+z = 1}:
solve({DotProduct(B-A,C-M)=0, DotProduct(C-A,B-M)=0, x+y+z = 1}); # barycentric coordinates of M
'M'=eval(M, %); # cartesian coordinates of M

@vv But  evala  works in other similar situations too. For example

restart;
M:=<a, -b; a/b, a*b>;
a:=2: b:=3:
evala(M);

@Susana30  For this example use the  surd  function:

A:=int((x^2)^(1/3), x);
surd(A^3, 3);

@Scot Gould  If we have already guessed that we can use the well-known difference of squares formula, then the process the factoring can be automated in Maple. The sum of any two terms can be expanded like this (Maple considers   a - b  as the sum  of operands  a  and  -b ):

restart;
expr:=x^10/36 - 4/25*y^24*z^8;
subsindets(expr, `+`, t->(sqrt(op(1,t))-sqrt(-op(2,t)))*(sqrt(op(1,t))+sqrt(-op(2,t)))) assuming positive;

It is worth noting that if you place an arrow over a symbol, then Maple does not consider this object as a vector, but considers it to be just a symbol:

                                     
                                      symbol

@SHIVAS 

subs({-5*sqrt(Sc*(S*Sc*S+4*Kr))=m1+5*S*Sc, ((-S*Sc+sqrt(Sc*(S^2*Sc+4*Kr))))=2*m2},Phi0_exact);

@Ali Hassani  Just replace  diff  with  u(x,t)  in the code.

@nm  It's easy to fix. But OP wrote  "I want all terms with 'diff' to be moved to the left side of the equation and all source terms to be moved to the right side of the equation."

Corrections in the last lines of your code:

Reff := s -> b*1/c*eval(S(t),F(s))*1/n;
Reff(100);
plot(Reff, 0..400, 0..2.1*10^(-6)); 

@C_R  OK. Thumb up.

@CaptNnFalcon  Cylindrical coordinates  x=r*cos(phi), y=r*sin(phi), z=z :

algsubs(x^2+y^2=r^2, Eq);
map(sqrt, %) assuming positive;
solve(%, z);
2*int(r,[z=0..%[1],r=2..6, phi=0..2*Pi]);

See the new answer to your previous question  https://mapleprimes.com/questions/238052-Condition-On-The-Colors-To-Illustrate#answer301034

Thank you all very much for your helpful answers!

@mmcdara  Thank you. I'm using Maple 2018 and don't have newer versions.

@dharr  Thanks for this. I've converted your comment into an answer. In essence, this is a ready-made help page for using prefix notation. In fact, this notation is very convenient and is widely used (in particular in programming), for example when the number of operands is large or a priori unknown.