SAT Math V

A good rule of thumb on the SAT is: If it looks like a quadratic equation, try to make it into a quadratic equation: If you try to solve for x, the best way is to move 12 to the same side of the equation, and then factor.

$x^2-x-12=0$ will factor as $(x-4)(x+3)$ . This means that $x$ could be $4$ or $-3$ . You can factor for $y$ in the same way, so $y$ could also be $4$ or $-3$ .

The greatest value for $x-y$ will be if $x=4$ and $y=-3$ , which is a difference of $\boxed{7}$ .

x=4,-3 y=4,-3 greatest (x-y)=4-(-3)=7