Home > INT3 > Chapter Ch1 > Lesson 1.1.2 > Problem1-21

1-21.

Factor each expression completely.

1. $x^2-x-72$

Find two numbers that multiply to $−72$ and add to $−1$.

1. $6x^2+48x$

There are only $2$ terms, so factor out the greatest common factor.

1. $x^2-8x+16$

Find two numbers that multiply to $16$ and add to $−8$.
You may find a diamond helpful for this.

1. $x^2-49$

Notice that this is the difference of squares.

$(x+7)(x−7)$