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5 votes
Solve for number eight

Solve for number eight-example-1
User Bello
by
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2 Answers

3 votes
You cannot have a negetive number inside a cube root. So we use an "i" instead.

This is how you do it:

5 \sqrt[3]{-27} + 18
\sqrt[3]{-27} becomes
3i

5(3i) + 18 multiply

15i + 18 reduce

3(5i + 6)


User Liam Kenneth
by
8.3k points
3 votes
so factor -27
-27=-1 times 3 times 3 times 3
∛(-1 times 3 times 3 times 3)=3 times ∛-1
remember that ∛-1=-1
2 times ∛-1=3 times -1=-3
now we have
5 times (-3)+18
5 times -3=-15
-15+18=3
answer is 3
User PJQuakJag
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8.3k points