SOLUTION: There are two numbers whose sum is 9 and the difference is five . What are the two numbers?

Algebra.Com
Question 447707: There are two numbers whose sum is 9 and the difference is five . What are the two numbers?
Found 3 solutions by stanbon, solver91311, Leaf W.:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
There are two numbers whose sum is 9 and the difference is five . What are the two numbers?
------
Equations:
x + y = 9
x - y = 5
----------------
Add and solve for "x":
2x = 14
x = 7
-----------
Solve for "y":
x + y = 9
7 + y = 9
y = 2
==================
Cheers,
Stan H.
============

Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!






Just solve the system. Hint: Already set up to solve by elimination.

John

My calculator said it, I believe it, that settles it
The Out Campaign: Scarlet Letter of Atheism


Answer by Leaf W.(135)   (Show Source): You can put this solution on YOUR website!
You can do this two ways: with one variable or with two variables. Personally, I think one variable is easier, but I'll show you both.
1. ONE variable
"two numbers WHOSE SUM IS 9"
x = one number
9 - x = other number (since the sum of the two numbers is 9, and one of them is x, then the other number would be the remainder or the difference when x is subtracted from 9
"the difference is five"
(9 - x) - x = 5
9 - x - x = 5
9 - 2x = 5
Subtract 9 from both sides: -2x = -4
Divide both sides by -2: x = 2
One of the numbers is 2. Plug this into the expression for the other number to find the other number.
9 - x
9 - 2
7
***THEREFORE, THE NUMBERS ARE 2 AND 7.
2. TWO variables
x = one number
y = other number
"whose sum is 9"
x + y = 9
"and the difference is five"
x - y = 5
Solve as a system of equations by "adding" the two equations.
x + y = 9
+(x - y = 5)
-----------
2x + 0y = 14
2x = 14
x = 7
Plug this value for x into either of the two equations and solve for y to find the value of the other number.
x + y = 9
7 + y = 9
y = 2
***THEREFORE, THE NUMBERS ARE TWO AND SEVEN.

RELATED QUESTIONS

there are two numbers whose sum is 9 and the difference is 5 what are the... (answered by nyc_function)
Find two numbers whose sum is 72 and whose difference is 10. The two numbers... (answered by ikleyn,MathTherapy)
what are the two numbers whose sum is 38 and whose difference is... (answered by John10)
The sum of two numbers is 55 and the difference is 9. What are the... (answered by fcabanski,lenny460)
The sum of two numbers is 59 and the difference is 9 . What are the... (answered by rothauserc)
The difference of two numbers is 9 and their sum is 37. what are the numbers? (answered by mananth)
the sum of two numbers is 9 and their difference is 6,what are the numbers? (answered by Fombitz)
the sum of two numbers is -9 and their difference is 31, what are the... (answered by addingup)
What are the two numbers whose sum is 23 and its absolute difference is 5? (answered by math-vortex)