Plss help I don’t understand this

Sadie computes the perimeter of a rectangle by adding the length, l, and width, w, and doubling this sum. eric computes the perimeter of a rectangle by doubling the length, l, doubling the width, w, and adding the doubled amounts. write an equation for sadie’s way of calculating the

Find the greatest common factor of the polynomial: 10x^5+15x^4-25x^3 10x^5 x^3 5x^3 5

Can someone me do math because i am having a breakdown rn because i don’t get it