Answer:
x = .16 or x = -.712
Explanation:
quadratic equation is, ax² + bx + c = 0
and quadratic formula is, x = -b ± √b² - 4ac / 2a
given equation is, 9x² + 5x - 1 = 0
a = 9, b = 5, c = -1
by substituting the values in the quadratic formula,
x = -5 ± √5² - 4*9*-1 / 2(9)
= -5 ± √25+36/18
= -5 ± √61 / 18
= -5 ± 7.81 / 18
= -5 + 7.81 / 18, -5 - 7.81 / 18
= 2.81/18, -12.81/18
= .16, -.712