Solve. {d+e=2 {d−e=4 use the substitution method. there are an infinite number of solutions. there is no solution. the solution is (5, 1). the solution is (3, −1).

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

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

What are the solutions of the system? solve by graphing. y = -x^2 -6x - 7 y = 2