Solve 2x^2-8x-9=0

Evaluate

2 x^{2} - 8 x - 9 = 0

Substitute a= 2,b= - 8 and c= - 9 into the quadratic formula x = \frac{- b \pm b ^{2} - 4 a c}{2 a}

x = \frac{8 \pm ( - 8 ) ^{2} - 4 \times 2 ( - 9 )}{2 \times 2}

Simplify the expression

x = \frac{8 \pm ( - 8 ) ^{2} - 4 \times 2 ( - 9 )}{4}

Simplify the expression

More Steps

x = \frac{8 \pm 136}{4}

Simplify the radical expression

More Steps

x = \frac{8 \pm 2 34}{4}

Separate the equation into 2 possible cases

x = \frac{8 + 2 34}{4} x = \frac{8 - 2 34}{4}

Simplify the expression

More Steps

x = \frac{4 + 34}{2} x = \frac{8 - 2 34}{4}

Simplify the expression

More Steps

x = \frac{4 + 34}{2} x = \frac{4 - 34}{2}

Solution

x_{1} = \frac{4 - 34}{2}, x_{2} = \frac{4 + 34}{2}

Alternative Form

x_{1} \approx - 0.915476, x_{2} \approx 4.915476

Solve the quadratic equation