What is the answer to the eqaution -4.5= a- 8

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?

There are 45 questions on your math exam. you answered 810 of them correctly. how many questions did you answer correctly?

How to simply and write the answer n a whole number