A. Since a negative times a negative is a positive, (-5)(-9) would be 45.
B. 2 - 4 = -2
C. 12/(-4) = -3
D. Adding a negative is essentialy the same thing as subtracting, so -3 + (-7) is the same thing as -3 - 7, which equals -10.
Therefore, the only equation that results in a positive value is A.
