How do you find the value of two numbers if their sum is 12 and their difference is 4?

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Answer 1 · 2018-01-30T21:43:37

$a = 8$ .
$b = 4.$

Let $a$ and $b$ be the two numbers we are looking for. We know that their sum is 12, and that their difference is 4. Then, this means that:

$a + b = 12$ (1);

$a - b = 4$ (2).

If we sum equations (1) and (2):

$a + b + a - b = 12 + 4$ ;

$2a = 16$ ;

$a = 8$ .

Now we can take this value for $a$ and place it in either equations (1) or (2); which will yield the same result for $b$ :

$8 + b = 12$ ;

$b = 4.$

Hope it helped you!