To horizontally stretch a function \( g(x) = -x^3 + 1 \) by a factor of 2, you need to replace \( x \) with \( \frac{x}{2} \) in the function. This is because a horizontal stretch by a factor of \( c \) involves transforming the variable \( x \) to \( \frac{x}{c} \).
In this case, to stretch by a factor of 2, the transformation would be:
\[ g\left(\frac{x}{2}\right) = -\left(\frac{x}{2}\right)^3 + 1 \]
This can be rewritten as:
\[ h(x) = -\left(\frac{1}{2} x\right)^3 + 1 \]
The corresponding option from the choices you have is:
b(x) = - (0.2x)³ + 1
This is equivalent to \( -\left(\frac{1}{5} x\right)^3 + 1 \), which is also correct since \( 0.2 \) represents a compression rather than a correct stretch factor.
To keep the horizontal stretch by a factor of 2, you should find an option reflecting that. Since none match explicitly, we recognize that:
Final Correct Answer: \( b(x)=−(0.5x)^{3}+1 \) was the transformation needed for a proper stretch.
But since \( b(x) \) doesn't match the requirement, the correct transformation should be \(-\left( \frac{1}{2}x \right)^3 + 1\) showing your options only showed confusion with horizontal compression.
Final Summary: No correct choice provided; \( h(x) = -\left(\frac{x}{2}\right)^3 + 1 \) should fit provided options.