To find the absolute value of a complex number, you need to calculate the square root of the sum of the squares of its real and imaginary parts. In this case, the absolute value of a is denoted as |a|.
Given a = (-9, -12), let's calculate the absolute value of a, |a|:
|a| = √((-9)^2 + (-12)^2) = √(81 + 144) = √225 = 15
Therefore, the absolute value of a is 15.
