Step 1
remember:
[tex]\begin{gathered} a\cdot a=a^2 \\ (a+b)\left(c+d\right)=ac+ad+bc+bd \end{gathered}[/tex]break the parenthesis
(-7a*-3a)+(-7a*2)+(2*-3a)+(2)*(2)
make the operations
[tex]\begin{gathered} 21a^2+(-14a)+(-6a)+4 \\ 21a^2-14a-6a+4 \\ 21a^2-20a+4 \end{gathered}[/tex]and, that is the answer
