Answer:
[tex]12a^{3}-15a^{2}+36a[/tex]
Step-by-step explanation:
To solve this problem you must apply the procccedure shown below:
1. You have the following expression:
[tex]3a(4a^{2}-5a+12)[/tex]
2. Then, you must apply the Distributive property. In other words, you need to multiply [tex]3a[/tex] by each term inside the parentheses.
3. You need to remember the properties of exponents. When you have equal base, you only need to multiply the coefficients, write the base and add the exponents. Therefore, you have:
[tex]3a(4a^{2}-5a+12)=12a^{(2+1)}-15a^{(1+1)}+36a=12a^{3}-15a^{2}+36a[/tex]
