Brain cramp...evaluating functions?

Question

(x+h)^2 - 2(x+h)=

x^2+2xh+h^2-2x-2h

okay... I'm sure it's one of those "basic" math rules that I never knew or forgot..... but where does the +2xh part of the answer come from??

Answer 1

from the first part of the equation...

(x+h)^2

=(x+h)(x+h)

=x^2+xh+xh+h^2

=x^2+2xh+h^2

Answer 2

(a + b)^2 = (a + b) (a + b) = a^2 + ab + ba + b^2 = a^2 + 2ab + b^2. This is an identity. That's where the +2xh part comes from.

I hope that helps. :)

me07.

Answer 3

Have you leant the distributive law for multiplication before?

If a,b,c,d are four numbers,the law states that

a(b+c)=ab+ac, so

(a+b)(c+d)=

(a+b)c+(a+b)d=

ac+bc+ad+bd=>

(a+b)(a+b)= (if a=c and d=b)

aa+ba+ab+bb=

a^+2ab+b^2

Now you understand how comes the term 2xh.

Answer 4

(x + h) X (x + h) - 2(x + h)

xx + xh + hx + hh - 2x - 2h

x^2 +2hx + h^2 - 2x - 2h