Multiply the numbers on the left side of the multiplication sign.
7.2 * 6 = 43.2
Combine the exponents attached to the 10s.
2 + (- 7)
2 - 7
- 5
Your scientific notation should be 43.2 x 10⁻⁵.
As a way to check your answer:
7.2 x 10² = 720 (move the decimal to the right twice)
6 x 10⁻⁷ = 0.0000006 (move the decimal to the left 7 times because it's a negative exponent)
Multiply the two together on a calculator, you get 0.000432. If you move the decimal 5 times to the left on 43.2 (again, because it's a negative exponent), you get 0.000432. The answers match.