To simplify the expression \( 6x^4 \cdot 3x^2 \), the correct steps are:
- Multiply the coefficients (numbers): \( 6 \times 3 = 18 \).
- Add the exponents of \( x \): \( 4 + 2 = 6 \).
So, the simplified expression is \( 18x^6 \).
Therefore, the correct choice from the options provided is:
- Multiply 6 x 3 for the numbers; then add 2 + 4 for the exponent on x.