1. Move the decimal point:

* Start with 15.0 (the decimal is implied after the 5)

* Move the decimal point 5 places to the right (because the exponent is positive 5)

This gives us 150000.

2. Express as a number between 1 and 10 multiplied by a power of 10:

* 150000 can be written as 1.5 x 10⁵

Therefore, the scientific notation for 15 x 10⁵ is 1.5 x 10⁵.