Thread: Help with binomial expansions

Is there a quick way to expand: (3x + 5)(x - 7)?

Using a computer will be quite quick.

Its not a tricky one though, have you seen the F.O.I.L method?

Originally Posted by AJD

Is there a quick way to expand: (3x + 5)(x - 7)?

FOIL will be quickest but you can also use the distributive property

Originally Posted by AJD

Is there a quick way to expand: (3x + 5)(x - 7)?

This is a good example where you may say "and" instead of "plus".



We may also write

and or and

which is

and and and



The whole is the sum of the parts

WXXXXX
WXXXXX
YZZZZZ
YZZZZZ
YZZZZZ




which is the 3x multiplied by both in the 2nd brackets and 5 by both in the 2nd brackets.