Question 352742
Forward: You distribute a to each term inside the parentheses.
{{{a(b+c-d-e^2)=(a*b+a*c-a*d-a*e^2)}}}

Backward: All the terms have x in common you can pull it out of the parentheses.
{{{10x^2+3xy-xz+x=x(10x+3y-z+1)}}}