Question Details

If x=2+3, evaluate the value of the algebraic expression x3-3x.

Options

A

82+63

B

52+43

C

102+83

D

72+53

Show Answer

Correct Answer :

Option A

82+63

153+115

Solution :

The correct answer is 82+63.

Step 1: Understand the given information

We are given the value of x:

x=2+3

We need to evaluate the value of the algebraic expression:

x3-3x

Step 2: Calculate x3

Using the algebraic identity (a+b)3=a3+3a2b+3ab2+b3, set a=2 and b=3:

x3=(2+3)3

x3=(2)3+3(2)2(3)+3(2)(3)2+(3)3

Simplify each term individually:

(2)3=22

3(2)2(3)=3×2×3=63

3(2)(3)2=3×2×3=92

(3)3=33

Substitute these back into the expression for x3:

x3=22+63+92+33

Combine like terms:

x3=(22+92)+(63+33)

x3=112+93

Step 3: Calculate 3x

Multiply x by 3:

3x=3(2+3)

3x=32+33

Step 4: Evaluate x3-3x

Subtract 3x from x3:

x3-3x=(112+93)-(32+33)

x3-3x=112+93-32-33

Group terms with like radicals:

x3-3x=(112-32)+(93-33)

x3-3x=82+63

Hence, the evaluated value of the algebraic expression is 82+63.

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