Answer:
1. (-5x^2) ( -7x^4y)
-5x^2 . -7x^4 = 35x^6
= 35x^6y
2. (-15mn^4) (3m^2n) (-2m^3n)
(-45m^3n^5) (-2m^3n)
=90m^6n^6
3. 2a(4b - 5c + 2d)
2a . 4b = 8ab
2a . -5c = -10ac
2a . 2d = 4ad
= 8ab - 10ac + 4ad
4. (x+3) (x+5)
x . x = x^2
x. 5 = 5x
3 . x = 3x
3. 5 = 15
= x^2 + 8x + 15
5. (a+5) (a^2 + 2a + 1)
a . a^2 = a^3
a . 2a = 2a^4
a . 1 = 1
5 . a^2 = 5a^2
5 . 2a = 10a
5 . 1 = 5
= a^3 + 7a^2 + 11a + 5
