Solve x (x-40)=100

Question

Solve the quadratic equation

Solve using the quadratic formula

Solve by completing the square

Solve using the PQ formula

x_{1} = 20 - 105, x_{2} = 20 + 105

Alternative Form

x_{1} \approx - 2.36068, x_{2} \approx 42.36068

Evaluate

x (x - 40) = 100

Expand the expression

More Steps

x^{2} - 40 x = 100

Move the expression to the left side

x^{2} - 40 x - 100 = 0

Substitute a= 1,b= - 40 and c= - 100 into the quadratic formula x = \frac{- b \pm b ^{2} - 4 a c}{2 a}

x = \frac{40 \pm ( - 40 ) ^{2} - 4 ( - 100 )}{2}

Simplify the expression

More Steps

x = \frac{40 \pm 2000}{2}

Simplify the radical expression

More Steps

x = \frac{40 \pm 20 5}{2}

Separate the equation into 2 possible cases

x = \frac{40 + 20 5}{2} x = \frac{40 - 20 5}{2}

Simplify the expression

More Steps

x = 20 + 105 x = \frac{40 - 20 5}{2}

Simplify the expression

More Steps

x = 20 + 105 x = 20 - 105

Solution

x_{1} = 20 - 105, x_{2} = 20 + 105

Alternative Form

x_{1} \approx - 2.36068, x_{2} \approx 42.36068

Show Solution