If a > 0 and b < 0, then which of the following must be true.

ab > 0

a + b < 0

a - b > 0

a + b > 0

b - a > 0

We need to find the correct answer on the given choices:

If a > 0 and b 0

let’s give a specific example:

let’s have a = 1

and b =.20

Now, let’s try calculating if our answer is correct.

Thus a + b > 0

=> a + b

=> 1 +.20

=> 1.20

and 1.20 is greater than 0.

=>Therefore 1.20 > 0 = a + b > 0