Question 721308
Area of a rectangle is the product of length times width. So
{{{x^2-3x-10}}} must be the product of length times width. To find expressions for length and width, we factor {{{x^2-3x-10}}}:
(x-5)(x+2)
One of these is the length and one of them is the width. If the length has to be longer than the width, then x+2 is the length and x-5 is the width (because no matter what x may be, x+2 will always be more than x-5).