# Find two numbers where difference is 20 & the sum is -4

• Oct 27th 2010, 02:30 AM
Kick
Find two numbers where difference is 20 & the sum is -4
Find 2 numbers such that the difference between them is 20 and their sum is -4.

Is there a systematic way or method to solve this besides just guessing integers?

(p.s. No algebra allowed, this is a pre-algebra questions)
• Oct 27th 2010, 03:25 AM
Ackbeet
The only systematic way to solve this that I know of is to use linear algebra:

x - y = 20
x + y = -4.

Turn the crank.
• Oct 27th 2010, 03:35 AM
RHandford
Hi

A clue, one of the numbers you want is 8, can you work out the other number?
• Oct 27th 2010, 05:26 AM
HallsofIvy
Divide the difference equally between the two numbers.

Half of 20 is 10, half of -4 is -2. Add and subtract -2 to and from 10.

Think about what the signs should be.

(As Ackbeet implies "systematic" pretty much means algebra!)
• Oct 27th 2010, 10:33 AM
wonderboy1953
Quote:

Originally Posted by Kick
Find 2 numbers such that the difference between them is 20 and their sum is -4.

Is there a systematic way or method to solve this besides just guessing integers?

(p.s. No algebra allowed, this is a pre-algebra questions)

Two simultaneous equations is a systematic way towards solving that type of problem.