jabarkan bentuk perkalian berikut dengan sifat distributif a) (2x-3) (x+5) b) (3x-y) (x+y) c) (5m-1) (m+4)

a)
(2x - 3)(x + 5)
= (2x)(x) + (2x)(5) + (-3)(x) + (-3)(5)
= 2x² + 10x - 3x - 15
= 2x² + 7x - 15

b)
(3x - y)(x + y)
= (3x)(x) + (3x)(y) + (-y)(x) + (-y)(y)
= 3x² + 3xy - xy - y²
= 3x² + 2xy - y²

c)
(5m - 1)(m + 4)
= (5m)(m) + (5m)(4) + (-1)(m) + (-1)(4)
= 5m² + 20m - m - 4
= 5m² + 19m - 4