# Lesson 94 – Doodles Do Algebra

Today your child practices greatest common divisor some more.

1. Find the prime factors of $x^2+2x-3$ which are (x+3), (x-1). Then find the prime factors of $x^2+5x+6$ which are (x+2), (x+3). So the greatest common divisor is (x+3).
2. This problem you have to just divide $6a^2+7ax-3x^2$ by $6a^2+11ax+3x^2$ and find the greatest common divisor is 2a+3x.
3. The factors in $a^4-x^4$ are $(a^2+x^2)(a^2-x^2)$. The factors in $a^3+a^2x-ax^2-x^3$ are $(a+x)(a^2-x^2)$. So the greatest common divisor is $(a^2-x^2)$.