ax² + bx + c = 0 has solutions
x = ( -b ± √(b²-4ac) ) / 2a
a. 3x² +7x +2 = 0
x = ( -7 ±√ (7² - 4(3)(2)))/(2(3)) = (-7 ±√ (49-24))/6 = (-7 ±√25)/6 = (-7±5)/6 = -12/6 or -2/6
x = -2 or x = -1/3
b. 2x² -9x - 35 = 0
x = (9 ± √(9² - 4(2)(-35)))/(2(2)) = (9 ± √361 ) /4 = (9 ± 19)/4 = -10/4 or 28/4
x = -5/2 or x = 7
c. 8x² + 10x + 3 = 0
x = (-10 ± √(10² - 4(8)(3)))/16 = (-10 ± √4)/16 = (-10 ± 2)/16 = -12/16 or -8/16
x = -3/4 or x= -1/2
d. x² - 5x + 9 = 0
x = (5 ± √(5² - 4(9)))/2 = (5 ± √-11)/2 = (5 ± i√11)/2
(or no solution if you haven't gotten to complex numbers yet.)
