The multiplicative inverse is yet another call for "reciprocal", so the reciprocal of 3i is: one million / 3i yet we could desire to "comprehend the denominator": (one million / 3i)(i / i) = i / 3(-one million) = - i / 3 As for the 2d area, calculate the discriminant, the parabola is of the type: ax² + bx + c = 0 The discriminant is given by: ? = b² - 4ac ? = (-8)² - 4(2)(-4) = sixty 4 + 32 = ninety six while: ? < 0, imaginary or complicated roots ? = 0, one rational root (or 2 equivalent, rational roots) ? > 0, 2 different, actual roots. ? is a appropriate sq., 2 different, actual, rational roots. Now: ? > 0, so there are 2, distince actual roots. yet ninety six isn't a appropriate sq., so the roots would be irrational. the respond is (c)