Thực hiện phép tính a) (x+5)^2-x(x+10) b) (18x^6y^6-12x^5y^5+24x^3y^5): 6x^3y^5

a. ${(x+5)}^2-x(x+10)$ 

$=x^2+10x+25-x^2-10x$

$=(x^2-x^2)+(10x-10x)+25$

b) $(18x^6{y}^6-12x^5{y}^5+24x^3{y}^5):6x^3{y}^5$

$=18x^6{y}^6:6x^3{y}^5-12x^5{y}^5:6x^3{y}^5+24x^3{y}^5:6x^3{y}^5$

$=3x^{3}y-2x^2+4$