Jawabanmu

2014-09-02T21:54:29+07:00
(x-2)(x-5) sama dengan (a-b)(c-d) = ac-bc-ad+bd, jadi
(x-2)(x-5) adalah (xx-2x-5x+10) = (x^2-7x+10)
2014-09-02T21:58:36+07:00
(x-2) (x-5) = (a-b) (c-d) = ac-ad+bc+bd
x dikali x = x^2 [ac]
x dikali -5 = -5x [ad]
-2 dikali x = -2x [bc]
-2 dikali -5 = 10 [bd]
jadi x^2-5x-2x+10 = x^2-7x+10

note
^ = pangkat