What is the greatest common factor between 16 and 28? please answer and I hope you’re having a good day!!

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Giuseppi's pizza had orders for $931.00 of pizzas. the prices were $21 for a large pizza, 514 for a medium pizza, and $7 for a small pizza. the number of large pizzas was two less than four times the number of medium pizzas. thenumber of small pizzas was three more than three times the number of medium pizzas. how many of each size of pizza were ordered?

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?