Question

The sum of two numbers is 62, and their difference is 12. What are the numbers?

Answer 1

X + y = 62 

x - y = 12

Move x over so y is alone in one of the above equations,

y = 62-x

Now substitte in y

x-(62-x) = 12

x - 62 + x = 12

2x = 12 + 62

2x/2 = 74/2

x = 37

Now for y sub in the x!

x + y = 62

(37) + y = 62

y = 62 - 37

y = 25.

So 25 + 37 =62

and 37 - 25 = 12


Method 2 :
Start by stacking the 2 original equations from above,

x+y=62
x-y=12
You want to "cancel" out one of the variable so,

x+y=62
+  +  =  +
x - y =12

So then you add,

2x = 74

2x / 2 = 74 / 2

x = 37.

Now you can once again sub it back into the original equation to solve for y,

x+y=62
(37)+y=62
y=62-37
y=25

Hope this helps!