Question

expand this (3x-1/2x)3 ​

Answer 1

Answer:

-1

Explanation:

(3x-1/2x)^2

(3x)^2+(1/2x)^2-2x(3x)x1/2x

9x^2+1/4x^2

=-1

Answer 2

Concept

• A cubic equation in algebra is a one-variable equation of the form ax3+bx2+cx+d=0 where an is nonzero.
• The roots of the cubic function defined by this equation's left side are the answers to this equation.

Given

Expression  $(3x-\frac{1}{2x} )^3$ is given

Find

We have to expand the given expression

Solution

The steps are as follow:

• The given expression $(3x-\frac{1}{2x} )^3$ can be compare with $(a-b )^3$
• The solution of $(a-b)^3$ is $a^3-3a^2b +3ab^{2} - b^{3}$
• So the given expression will be expanded as follow:

$(3x-\frac{1}{2x} )^3\\\\a=3x\\\\b= \frac{1}{2x} \\\\(3x)^2 - 3(3x)^2 (\frac{1}{2x} )+3(3x)(\frac{1}{2x} )^2 + (\frac{1}{2x} )^3\\\\9x^2 -\frac{27x}{2} + \frac{9}{4x} + \frac{1}{8x^3}$

Hence the expansion of given expression $(3x-\frac{1}{2x} )^3$ will be $9x^2 -\frac{27x}{2} + \frac{9}{4x} + \frac{1}{8x^3}$

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