Question

si ab = 2a +4b hallar a + b

Answer 1

ec.1 ab=2a+4b
igualas a cero
ec.2 ab-2a-4b=0

factorizas a de la ec.2
a(b-2)-4b=0
despejas a
a=4b/(b-2)

ahora factorizas b de la ec.2
b(a-4)-2a=0
b=2a/(a-4)

ahora a+b=
(4b/(b-2))+(2a/(a-4))