Which shows the factored form of x2 – 12x – 45? (x + 3)(x – 15)
(x – 3)(x – 15)
(x + 3)(x + 15)
(x – 3)(x + 15)

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

Plz hurry evaluate the expression a+b where a=8 and b=19

Ascientist has 50 grams of a radioactive element. the amount of radioactive element remaining after t days can be determined using the equation (1) after two days the scientist receives a second shipment of 50 grams of the same element. the equation used to represent the amount of shipment 2 remaining after t days is 10) - 50 which of the following is an equivalent form of the expression for the amount remaining in shipment 2? what’s the answer?