MCQ
If x is a positive real number and x2 = 2, then x3 =
- A$\sqrt{2}$
- B$2\sqrt{2}$
- C$3\sqrt{2}$
- D$4$
✓
Answer
- $2\sqrt{2}$
Solution:
We have to find x3 providedx2 = 2 So,
By raising both sides to the power $\frac{1}{2}$
$\text{x}^{2\times\frac{1}{2}}=2^{\frac{1}{2}}$
$\text{x}^{2\times\frac{1}{2}}=\sqrt{2}$
$\text{x}=\sqrt{2}$
By substituting $\text{x}=\sqrt{2}$ in x3 we get
$\text{x}^3\big(\sqrt{2}\big)^3$
$=\sqrt{2}\times\sqrt{2}\times\sqrt{2}$
$=2\sqrt{2}$
The value of x3 is $2\sqrt{2}$
Hence the correct choice is b.
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