Answer is:
option2
\( -0.366 \)
Solution:
Parallel tangents mean slopes are the same, which means first derivatives are the same.
\( f'(x) = 6e^{3x} \)
\( g'(x) = 15x^2 \)
\( 6e^{3x} = 15x^2 \)
Now, graph and find the zeroes of \( 6e^{3x} - 15x^2 \)
\( x = -0.366 \)
