# Exponents, unlike mulitiplication, do NOT "distribute" over addition.

• Feb 23rd 2010, 09:40 AM
sherlewman
Exponents, unlike mulitiplication, do NOT "distribute" over addition.
i think this is supposed to be an example of an exponent not "distributing over addition?

(x-2)2

(x – 2)2 = (x – 2)(x – 2) = xx – 2x – 2x + 4 = x2 – 4x + 4.

I don't understand where they are getting the -2x from?

is this question even right?

• Feb 23rd 2010, 09:49 AM
icefirez
basic formula

\$\displaystyle (a-b)^2= a^2 - 2*a*b + b^2\$
so we got

\$\displaystyle (x-2)^2=(x-2)(x-2)= x*x-x*2-2*x-2(-2)=x^2-4x+4\$

we are multiplying each terms with others; x with two other terms in other perentecies and than 2 with other terms in other perentecies same as x(x-2)=x^2-2x and ading other term -2(x-2)=-2x+4

hope this is understandable
• Feb 23rd 2010, 09:54 AM
earboth
Quote:

Originally Posted by sherlewman
i think this is supposed to be an example of an exponent not "distributing over addition?

(x-2)2

(x – 2)2 = (x – 2)(x – 2) = xx – 2x – 2x + 4 = x2 – 4x + 4.

I don't understand where they are getting the -2x from?

is this question even right?