Question

the sum of two numbers is 15. if one number is subtracted from the other, the result is 1. Find the numbers

Answer 1

the sum of two numbers is 15. if one number is subtracted from the other, the result is 1. Find the numbers

x + y = 15
x - y = 1

Add the two equations.

  x + y = 15
+(x - y = 1)
---------------
 2x       = 16
2x = 16
x = 8

x + y = 15
8 + y = 15
y = 7

The numbers are 8 and 7

Answer 2

First, write down all the information you know.

x + y = 15
x - y = 1

Then, isolate one variable in one of the equations

x - y = 1
x = 1 + y

So now we have a value for x, namely, x = 1 + y
Substitute this back into one of the original equations

x + y = 15
(1 + y) + y = 15
y + y = 15 - 1
2y = 14
y = 14/2
y = 7

Now we have one of the numbers, which we called y. Substitute this into one of the equations to get your x.

x + y = 15
x + 7 = 15
x = 15 - 7
x = 8

Now we have both our numbers, 6, and 9

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