Which algebraic expression has like terms?

Rewrite the following without an exponent. (5/8)-1

Find the length of the following tangent segments to the circles centered at o and o' whose radii are 5 and 3 respectively and the distance between o and o' is 12. what is the tangent segment of cd?

Idon’t understand! use slope intercept form to solve: through: (2,5) slope= undefined