Solve x^2-4x-1 - ScanMath

Evaluate

x^{2} - 4 x - 1

To find the roots of the expression,set the expression equal to 0

x^{2} - 4 x - 1 = 0

Substitute a= 1,b= - 4 and c= - 1 into the quadratic formula x = \frac{- b \pm b ^{2} - 4 a c}{2 a}

x = \frac{4 \pm ( - 4 ) ^{2} - 4 ( - 1 )}{2}

Simplify the expression

More Steps

x = \frac{4 \pm 20}{2}

Simplify the radical expression

More Steps

x = \frac{4 \pm 2 5}{2}

Separate the equation into 2 possible cases

x = \frac{4 + 2 5}{2} x = \frac{4 - 2 5}{2}

Simplify the expression

More Steps

x = 2 + 5 x = \frac{4 - 2 5}{2}

Simplify the expression

More Steps

x = 2 + 5 x = 2 - 5

Solution

x_{1} = 2 - 5, x_{2} = 2 + 5

Alternative Form

x_{1} \approx - 0.236068, x_{2} \approx 4.236068

Find the roots