Question

When we use (-)(-) = +
and
when we use (-)(-) = -​

Answer 1

NO .

When we use (-) (-) = +

(-) (+) = -

(+) (-) = -

(+) (+) = +

This is correct.

Answer 2

Answer:

(-) × (-) = (+) {when multiply}

and

(-) + (-) = (-) {when add}