Question 767254
16. x8 - 16x4 
A  x4(x - 2)(x + 2)(x2 + 4) 
B (x4 + 4x2)2 
C (x4 - 4x2)2 
D (x4 + 4x2)(x4 - 4x2) 
E x4(x4 - 16) 
F cannot be factored 


ans: A  x4(x - 2)(x + 2)(x2 + 4)

17. a4 + 1 
A (a2 + 1)2 
B (a2 - 1)(a2 - 1) 
C a2(a2 + 1) 
D (a2 + 1)(a2 - 1) 
E a2 (a + 1)2 
F cannot be factored 


ans: F cannot be factored 

18. 3a4 + 81a 
A (a + 3)(a2 + 3a + 9) 
B (3a2 + 3)(a2 - 3a + 9) 
C (a2 + 3a)(a2 - 3a + 9) 
D 3a(a + 3)(a2 - 3a + 9) 
E (3a + 3)(a2 + 3a - 9) 
F cannot be factored 

ans:D 3a(a + 3)(a2 - 3a + 9)


19. x3 + x2 - x - 1 
A (x - 1)(x2 + 2x + 1) 
B (x + 1)4 
C (x2 + 1)2 
D (x + 1)3 
E (x - 1)(x + 1)2 
F cannot be factored 


A (x - 1)(x2 + 2x + 1)