The square of a number is always two numbers multiplied together. A positive times a positive is always positive, and a negative times a negative is always positive.

The answer is always positive. If the signs are the same (positive by positive, negative by negative), then the quotient is always positive. If the signs are different (positive by negative, negative by positive), then the quotient is always negative.

Yes, a negative number subtracted from a positive number will always be positive. Subtracting a negative number is the same as adding the opposite of the negative number. The opposite of a negative number is always positive. A positive number plus a positive number is always positive.

Two people would need to cosign an agreement when for example, parents need to cosign the loan application for their child or to help a friend in need.