Solve x^2 + 4x = 4 for x by completing the square.

x = −4
x = 0
x equals plus or minus 2 times the square root of 2 plus 2
x equals plus or minus 2 times the square root of 2 minus 2

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days