Ask your own question, for FREE!
Mathematics 18 Online
OpenStudy (aravindg):

how to easily multiply (x-2)(x-3)(x-5)?

OpenStudy (anonymous):

Distributive law

OpenStudy (amistre64):

do you know how to multiply numbers? like 35(56)?

OpenStudy (aravindg):

easy way plz

OpenStudy (amistre64):

math isnt about "easy" its about discipline

OpenStudy (aravindg):

like not opening brackets mechanically

OpenStudy (amistre64):

if you wanna memorize a bunch of formulas to try to sort thru, thats up to you i spose

OpenStudy (anonymous):

lol there is no royal road to algebra

OpenStudy (anonymous):

ok really it was "there is no royal road to geometry" but the point is the same

OpenStudy (anonymous):

It doesn't matter how you do it, you will be using the following property of the real number field: distributivity of multiplication over addition

OpenStudy (amistre64):

(x-2)(x-3)(x-5) ; x=10 (8)(7)(5) 56(5) = 280; 200 + 50 - 30; 2x^2 +5x -30 .. got no idea

OpenStudy (anonymous):

lost him/her i am sure

OpenStudy (amistre64):

indeed, but the notion is intriguing lol

OpenStudy (amistre64):

x^2-5x +6 x-5 --------- x^3-5x^2+6x -5x^2+25x-30 ------------------ x^3-10x^2+31x-30 ... i wasnt even close :)

OpenStudy (amistre64):

the "easy" way for me is to stack them up like numbers (they are numbers) and multiply like usual

OpenStudy (anonymous):

Applying the property recursively until expansion is complete: \[\begin{eqnarray*} (x-2)(x-3)(x-5) &=& (x(x-2)-3(x-2))(x-5) \\ &=& (x^2 - 2x - 3x + 6)(x-5) \\ &=& x^2(x-5) - 2x(x-5) - 3x(x-5) + 6(x-5) \\ &=& x^3-10x^2+31x-30 \end{eqnarray*}\]

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!