I'm assuming you meant 1.5 × 10⁴. Remember, when we write in standard form, you need to use ^ to denote it's 'to the power of'. So it would be 1.5 × 10^4.
I'm also assuming you meant in decimal form, because that's already in standard form.
However, the answer is 15,000. This is because you lose one zero when multiplying a decimal with one number after it. For each number after the decimal, you take off a zero. Therefore, the end number is 15,000.
Point I think is the anwser
First blank: Substitution or transitive property of equality
Second blank: Subtraction property of equality
This is the worksheet I’m doing https://www.manhassetschools.org/cms/lib8/NY01913789/Centricity/Domain/710/Aim%2082%20Pd%209%20KEY.pdf
Water can freeze at 32 degrees f