Respuesta :
Let's solve this problem step by step.
First. The sum of a squared and b
[tex]a^2+b[/tex]
Second. 7 times the sum of a squared and b
[tex]7(a^2+b)[/tex]
Third. 4 times the sum of a squared and b
[tex]4(a^2+b)[/tex]
Finally. 7 times the sum of a squared and b minus 4 times the sum of a squared and b
[tex]7(a^2+b)-4(a^2+b)[/tex]
And this is:
[tex]\boxed{7(a^2+b)-4(a^2+b)=3(a^2+b)}[/tex]