Write a system of equation based on the number For an instance, the two numbers are a and b. "The sum of two numbers is 59" can be written as follows. ⇒ a + b = 59 <em>(first equation) </em>"The difference is 15" can be written as follows. ⇒ a - b = 15 <em>(second equation)</em>
Solve the system of equation by elimination/substitution method. First, eliminate b to find the value of a. a + b = 59 a - b = 15 --------------- + (add) 2a = 74 a = 74/2 a = 37
Second, substitute 37 as a in one of the equations a + b = 59 37 + b = 59 b = 59 - 37 b = 22
