Respuesta :

9)

(x+10)²

(x +10) (x+10)

We will take he x in the first bracket and then use it to multiply the second bracket

Also we will take the 10 in the first bracket and then use it to multiply the second bracket

That is:

x(x+10) + 10(x+10)

x² + 10x + 10x + 100

x² + 20x + 100