The sum of two numbers is 40, and their difference is 190. Find the two numbers.

Help plz. An explanation of the answer would be great too.

a + b = 40
a − b = 190

Solving the second equation for a, we get a = b + 190.

Plugging in this new equation into the first equation:
a + b = 40
(b + 190) + b = 40
2b + 190 = 40
2b = -150
b = -75

Now that we have b, we can plug into one of the equations and solve for a:
a + b = 40
a − 75 = 40
a = 115

So a = 115 and b = -75.