3ˣ (x² - 3)
Basically, just multiply everything together.
Step 1 : 3x × x² = 3x³ because when multiplying exponents, all you're really doing is adding them on top. So, x + 2x = 3x! But, they are exponents, so you get 3x³.
Step 2 : 3x ˣ × (-3) = -9ˣ
Now, our new question is : 3x³ - 9x
You wouldn't simplify this because x³ is NOT the same as x.
~Hope I helped!~