Question

Find two numbers with a sum of 20 and a difference of 14.

Answer 1

The anwser is 17 and 3. 17+3=20, and the difference is 14!

Answer 2

We can easily find this using equations.  what do we know?

X + Y = 20  and
-(X - Y = 14)        subtract the two equations..

X + Y = 20
-X + y = -14

2Y = 6
Y = 3        (our first number)  (put this into an original equation and solve)

X + Y = 20
X + 3 = 20    subtract 3 from both sides
X = 17

gives us our answer ....... 3 and 17