Roots and Radicals 37
(^3) −≠ 27 − 9. You do not divide
by 3 to get a cube root.
e.^3 − 77 ⋅− ⋅− 7
f.^3 bbbbb
Solution
a.^3 −^27
Step 1. Find the principal cube root of − 27.
− 333 ⋅−⋅− =− 27 , so^3 −= 27 − 3.
b.^8
125
3
Step 1. Find the principal cube root of
8
125
.
2
5
2
5
2
5
8
125
⋅⋅= , so8
125
2
5
(^3) =.
c.^30. 008
Step 1. Find the principal cube root of 0.008.
() 02. 2 () 0202 ... () 002. = 0. 008 , so^30 .. 008008 = 002.
d.^3 − 1
Step 1. Find the principal cube root of − 1.
− 111 ⋅− ⋅− =− 1 , so^3 − 11 =−.
e.^3 − 77 ⋅− ⋅− 7
Step 1. Find the principal cube root of − 777 ⋅−⋅−.
(^3) − 777 ⋅−⋅− =− 7
f.^3 bbbbb
Step 1. Find the principal cube root of bbbbb.
(^3) bbbbb =b