Answer
No, $(x^{2})^3 \ne x^{5}$
No, $(2x^{4})^{3}\ne(2x^{12})$
Work Step by Step
When we raise a power to a new power we multiply the exponents,
So, $(x^{2})^3 = x^{2\times3} = x^{6}$ which is not equal to $x^{5}$
B.
$(2x^{4})^{3}=(2^{3}x^{4\times3})=(8x^{12})$ which is not equal to $(2x^{12})$
