We have c = -b and c < -a, which means -b < -a. Dividing both sides by -1, we get b > a. Since ab = 1, we know that a and b must be reciprocals.
From bc = -9, we substitute c = -b to get b(-b) = -9. Simplifying, we have b² = -9. Since b is positive (b > a), we take the positive square root of -9 to get b = 3.
Since a and b are reciprocals, we have a = 1/3. Therefore, a + b = 1/3 + 3 = 1/3 + 9/3 = 10/3.
So, the value of a + b is 10/3.
If ab = 1, bc = –9, c = –b and c < –a, what is the value of a + b? Express your
answer as a mixed number.
1 answer