Question

A. (2x +1) (3x + 5) =
b. (a - 3) (2a + 5) =
c. (p - 3) (p - 7) =
d. (7p - 3) (8p + 7) =
Pake caranya

Answer 1

Yang harus diinget dari perkalian suku dua:
1.Suku pertama mengalikan suku dua.
Contoh:
(a+b)(a-b)
=a²-ab+ab-b²
=a²-b²

atau bisa di jabarkan kayak gini:
(a×a)-(axb)+(bxa)-(bxb)
=a²-ab+ab-b²
=a²-b²

Jadi Caranya:
1.(2x+1)(3x+5)
=6x²+10x+3x+5
=6x²+13 x +5

Cara lain:
(2x.3x)+(2x.5)+(1.3x)+(1.5)
=6x²+10x+3x+5
=6x²+13x+5

2.(a-3)(2a+5)
=2a²+5a-6a-15
=2a²-a-15 

Cara lain kayak tadi aja:
(a.2a)+(a.5)-(3.2a)-(3.5)
=2a²+5a-6a-15
=2a²-a-15

3..(p-3)(p-7)
=p²-7p-3p+21
=p²-10p+21

Alternatif:
(p.p)-(p.7)-(3.p)+(3.7)
=p²-7p-3p+21
=p²-10p+21

4.(7p-3)(8p+7)
=56p²+49p-24p-21
=56p²+25p-21

Alternatif:
(7p.8p)+(7p.7)-(3.8p)-(3.7)
=56p²+49p-24p-21
=56p²+25-21


Udah ngerti kan??? Semoga membantu :)