What is the highest common algebraic factor of the terms $9x$9x and $8x$8x?
What is the highest common algebraic factor of the terms $9xn$9xn and $4ax$4ax?
What is the highest common algebraic factor of the terms $18b^2n$18b2n and $7b^2m$7b2m?
What is the highest common algebraic factor of the terms $13y^2an$13y2an and $17my^2b$17my2b?