Posted by parul on Tuesday, May 29, 2012 at 10:02pm.
the volume of a cubical solid is given by following expressions.find the side of field.
a)8a^3+b^3+12a^2 b+6ab^2.
b)27125a^3135a+225a^2.
c)27a^31/2169a^2/2+a/4.
d)x^31/x633x+3/x.
plz help me till 2 o'clock...

math  MathMate, Tuesday, May 29, 2012 at 10:31pm
8a^3+b^3+12a^2 b+6ab^2
Factor into a cube using the identity:
(x+y)^3 = x^3+3x^2y+3xy^2+y^3
a)8a^3+b^3+12a^2 b+6ab^2.
can be factorized into (2a+b)^3
for b)27125a^3135a+225a^2.
note the terms 27 and 125a^3 are perfect cubes, which gives you the hints
27=3^3, 125a^3=(5a)^3
27a^31/2169a^2/2+a/4.
again, 27a^3=(3a)^3, and 1/216=(1/6)^3
d)x^31/x633x+3/x.
is probably a typo, should read:
d)x^31/x^33x+3/x.
Again, use 1/x^3=(1/x)^3 and x^3
now use the identity.