Lucy M.
asked 12/16/20the sum of the two numbers is 13 and the difference is five what are the two numbers?
2 Answers By Expert Tutors
Chris S. answered 12/22/20
Patient, Flexible Math Teacher with 15+ years teaching experience!
Since the sum (addition) of two numbers is 13, we have to solve for A + B = 13. We also know the difference (subtraction) of two numbers is 5, we have to solve for A - B = 5.
A + B = 13
A - B = 5
By combining these two equations, the left side of the equation has A + A = 2A, while B - B cancels each other out. On the right side of the equation, we have 13 + 5 = 18. We now have 2A = 18. In order to get A by itself, we must divide by 2. In order to keep our equation balanced, whatever we do to the left side we must also do to the right side. 2A / 2 = A, and 18 / 2 = 9. Therefore, A = 9.
Now we go back to the original equations and substitute for 9 for A. Since 9 + B = 13, then B would equal 4. You could subtract 9 from both the left side and right side to keep them balanced, leaving you with B = 4. You can confirm your answer by solving the second equation and substitute 9 for A again. Since 9 - B = 5, then B would equal 4. You can double check your answer by substituting A=9 and B=4 into both equations to verify they now have true statements. 9 + 4 = 13, and 9 - 5 = 4, so we have indeed solved correctly.
Aaliyah C.
this was helpfull11/29/21

Patrick B. answered 12/16/20
Math and computer tutor/teacher
X + y = 13
X-y=5
Aodds them together
2x= 18
X=9
9 and 4
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Lucy M.
i was on prodigy12/16/20