F(x)= -x^2 -3 (hope this helps)
Isabella’s error is Isabella should have divided the product of 12π and 9 by 3 to get V = 12π(9)/3 option fourth is correct.
<h3>What is a cone?</h3>
It is defined as a three-dimensional shape in which the base is a circular shape and the diameter of the circle decreases as we move from the circular base to the vertex.

Isabella equation:

The area of the base = 12π square cm

Thus, Isabella’s error is Isabella should have divided the product of 12π and 9 by 3 to get V = 12π(9)/3 option fourth is correct.
Learn more about the cone here:
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The completely factored equation is (a²b - 5)(4a²b - 1)
<h3>How to factor equation?</h3>
4a⁴b² - 21a²b + 5 = 0
let's expand the equation
Therefore,
4a⁴b² - 21a²b + 5 = 0
4a⁴b² - 20a²b - a²b + 5 = 0
Rearrange the equation
4a⁴b² - a²b - 20a²b + 5 = 0
Let's factorise the equation
4a⁴b² - a²b - 20a²b + 5 = 0
a²b(4a²b - 1) - 5(4a²b - 1) = 0
Therefore, the completely factored equation is as follows:
a²b(4a²b - 1) - 5(4a²b - 1) = 0
(a²b - 5)(4a²b - 1)
learn more on equation here: brainly.com/question/8842252
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