Name the property used in each step?

[valentino]

i've always had problems with properties.. i honestly don't know how i passed year 9 and 10 when i haven't learned anything much.. seriously. (as long as we had writing on our homework papers, you get full credit. didn't really matter if the answers were right, only mattered on tests)

anyway.. i need help.

x + (x + 5) (GIVEN)
= (x + x) + 5 (?)
= (1 • x + 1 • x) + 5 (?)
= (1 + 1)x + 5 (?)
= 2x + 5 (SUBSTITUTION)

please help. also, is there a site with all of these properties and examples of them?

[wattekinson86]

This seems to be a fairly complete basic list:
http://www.themathlab.com/geometry/mathcourt/level1/algebrareasons.htm