Question

Find the value of two numbers if their sum is 23 and their difference is 5

Answer 1

Let the two numbers be represented by x and y respectively.

Then x + y = 23, and x - y = 5.  

Solve this system of linear equations for x and y.  Start by rearranging them vertically:

x + y = 23

x - y = 5

---------------   Combining the two equations eliminates y:

2x = 28.

Then x = 14.  If x = 14, then 14 + y = 23, and y = 9..

The solution is (14, 9);  that is, x = 14 and y = 9.