How do you write the expression (y-3)(y-3)(y-3) using exponents?

1 Answer
Jan 11, 2017

(y-3)(y-3)(y-3)=(y-3)^3=y^3-9y^2+27y-27

Explanation:

This is a product of three binomials, who are all the same i.e. (y-3)(y-3)(y-3).

We can write it simply as (y-3)^3.

For actual mutiplication, we use distributive property, first over (y-3)(y-3) and then multiplying the result by (y-3)

(y-3)(y-3)

= y(y-3)-3(y-3)

= yxxy-3xxy-3xxy-3xx(-3)

= y^2-3y-3y+9

= y^2-6y+9

and now multiplying above again by (y-3)

(y-3)(y-3)(y-3)

= (y-3)(y^2-6y+9)

= y(y^2-6y+9)-3(y^2-6y+9)

= yxxy^2-6yxxy+9xxy-3xxy^2-3xx(-6y)-3xx9

= y^3-6y^2+9y-3y^2+18y-27

= y^3-9y^2+27y-27