Ricardo has 898 sports cards. There are 15 more than three times as many football cards as basketball cards. Write a system of equations that can be used to determine the number of football cards, f, and basketball cards, b.

Which product is positive a is 2/5 -8/9 -1/3 -2/7 b is -2/5 8/9 -1/3 -2/7 c is 2/5 8/9 1/3 -2/7 d is -2/5 -8/9 1/3 2/7

What number should be added to both sides of the equation to complete this square? x^2-10x=7

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning