Answer:
[tex]-21a^{3}+12a[/tex]
Step-by-step explanation:
We are given that
[tex]-3a\cdot (7a^2-4)[/tex]
We have to find the product .
To find the product we will multiply -3a with each term given in the bracket
[tex]-3a(7a^2)-3a(-4)[/tex]
[tex]-21a^{1+2}+12a[/tex]
By using the formula
[tex]a^{x}\cdot a^{y}=a^{x+y}[/tex]
[tex]-21a^{3}+12a[/tex]
Hence,
[tex]-3a\cdot (7a^2-4)=-21a^{3}+12a[/tex]
