Question 299793
Identify the roots of -3x^3 - 21x^2 + 72x + 540 = 0. State the multiplicity of each root.
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Divide by -3
{{{x^3 + 7x^2 - 24x - 180 = 0}}}
Check for integer roots.  180 has factors of 1,2,3,4,5,6,9,10,12 & 15
Sub each one for x, both + and minus, and check for a zero.  I would use Excel to try them.
Once you find a root, then it becomes a quadratic.
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Post the other problems one at a time.  Tutors are more likely to do one problem than a list of them.