[tex] 2x^{2} [/tex] + 9x = 8 Subtract 8 from both sides
[tex] 2x^{2} [/tex] + 9x -8 = 0 Plug these into the Quadratic Formula
a = 2 , b = 9 , c = -8
x = [tex] \frac-{b (+ or -) \sqrt{ b^{2} - 4ac} }{2a} [/tex] Plug in the values
x = [tex] \frac{-9 (+ or -) \sqrt{ 9^{2}-4(2)(-8) } }{2(2)} [/tex] Multiply 2 and 2
x = [tex] \frac{-9 (+ or -) \sqrt{ 9^{2}-4(2)(-8) } }{4} [/tex] Multiply -4 and 2
x = [tex] \frac{-9 (+ or -) \sqrt{ 9^{2}-8(-8) } }{4} [/tex] Multiply -8 and -8
x = [tex] \frac{-9 (+ or -) \sqrt{ 9^{2}+64} }{4} [/tex] Square 9
x = [tex] \frac{-9 (+ or -) \sqrt{81 + 64} }{4} [/tex] Add 81 and 64
x = [tex] \frac{-9 (+ or -) \sqrt{145} }{4} [/tex] Take apart the (+ or -)
x = [tex] \frac{-9 + \sqrt{145} }{4} [/tex] and [tex] \frac{-9 - \sqrt{145} }{4} [/tex] Find the square root of 145
x ≈ [tex] \frac{-9 +12.0415945788}{4} [/tex] or [tex] \frac{-9 -12.0415945788 }{4} [/tex] Add -9 and the decimal , Subtract -9 and the decimal
x ≈ [tex] \frac{3.0415945788}{4} [/tex] or [tex] \frac{-21.0415945788}{4} [/tex] Divide both fractions
x ≈ 0.7603986447 or -5.2603986447 Round to the nearest hundredth (_._x)
x ≈ 0.76 or -5.26
