
Tamara J. answered 02/20/13
Math Tutoring - Algebra and Calculus (all levels)
(x + 4)2 = -13
Take the square root of both sides of the equation:
√(x + 4)2 = √(-13)
x + 4 = ± √(-13)
The square root of a negative number is not a real number. Recall that the imaginary number, i, is defined as the square root of -1. That is, i = √(-1).
So, since the square root of -13 is equal to the product of the square root of -1 and the square root of 13, we can generate a solution to x that is in the form of a complex number:
x + 4 = ± √(-13)
x + 4 = ± √(-1)·√(13)
x + 4 = ± i√(13)
Solve for x by subtracting 4 from both sides of the equation:
x = -4 ± i√(13)
Thus, there are two solutions for x: x = -4 + i√(13) and x = -4 - i√(13)