solve for c.
a(b − c)=d
a.c=ab d/a
b.c=d − ab/a
c.c=ab − d/b
d.c=ab − d/a
a(b − c)=d
a.c=ab d/a
b.c=d − ab/a
c.c=ab − d/b
d.c=ab − d/a