13. Write the following as a polynomial without parentheses: (-2z – 9)(7z + 6)
Ans.
(-2z – 9)(7z + 6)=-14z^2-12z-63z-54
=-14z^2-75z-54

14. Factor the following: 36x^5-6x^2+18x^3
Ans.
36x^5+18x^3-6x^2=6x^2 (6x^3+3x-1)

15. Simplify: ((-9x^5)/(7y^2 ))^2
Ans.
((-9x^5)/(7y^2 ))^2=(81x^10)/(14y^4 )

16. 16 is 40% of what?
Ans.
16=40/100 n
16=0.4n
n=16/0.4=40

17. Solve the following inequality: -5(3-x)≤-9-8
Ans.
-5(3-x)≤-9-8=-15+5x≤-17
add 15 both side,
5x≤-17+15
5x≤-2
Divide both side with 5
x≤-2/5→x≤-0.4