Question

Find two numbers, if Their sum is −7 and their difference is 14

Answer 1

3.5 and -10.5

Explanation:

i checked, its correct

Answer 2

Let
a------------> first number
b------------> second number

we know that
a+b=-7--------> a=-7-b----------> equation 1
a-b=14--------> equation 2

I substitute 1 in 2

(-7-b)-b=14-------------> -7-b-b=14----------> -7-2b=14-------> 2b=-7-14
2b=-21---------> b=-10.5
a=-7-b-------> a=-7-(-10.5)-----> a=-7+10.5------> a=3.5

the answer is
the two numbers are
a=3.5
and
b=-10.5