1. (a + b)(c+d) =2. (a-b)2 = tolong bantu ya besok dikumpulkan kalau bisa pakai cara

1.
(a + b)(c + d) = (a)(c) + (a)(d) + (b)(c) + (b)(d)
                      = ac + ad + bc + bd

2.
(a-b)² = (a)² + 2(a)(-b) + (-b)²
          = a² – 2ab + b²

1. (a + b) (c+d)
= ac + ad + bc + bd
2.
*kalo soalnya (a – b) dikali 2
= (a – b) . 2
= 2a – 2b
*kalo soalnya (a – b) pangkat 2
= (a – b) pgkt 2
= (a – b) (a-b)
= a pgkt 2 – ab – ab + b pgkt 2
= a pgkt 2 -2ab + b pgkt 2