SOLUTION: can you please help me solve the question: determeine the vales for the variables for which the expression is defined as a real number square of 3X^3-27X

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Question 92533: can you please help me solve the question:

determeine the vales for the variables for which the expression is defined as a real number
square of 3X^3-27X
Answer by chitra(359) About Me  (Show Source):
You can put this solution on YOUR website!
square of 3X^3-27X

This can be written as:

%283x%5E3+-+27x%29%5E2

For the above expression to be valid and defined on real numbers we equate it to zero.

%283x%5E3+-+27x%29%5E2 = 0

%283x%5E3+-+27x%29 = 0

==> %283x%5E3%29+=+27x

==> %283x%5E2%29+=+27 one x term gets calcelled out


==> x%5E2+=+%2827%2F3%29


==> x%5E2+=+9

==> Squaring both sides, we get:

x+=+%2B+-+9

thus the solution

Regards