x*2+4=0 x*2=-4 x=do root of -4 can't possible to do root of -4

x² + 4 = 0 - 4 - 4 x² = -4 x = 2i x² - 6x + 7 = 0 x = -(-6) +/- √((-6)² - 4(1)(7)) 2(1) x = 6 +/- √(36 - 28) 2 x = 6 +/- √(8) 2 x = 6 +/- 2√(2) 2 x = 3 + √(2) x = 3 + √(2) x = 3 - √(2)