Question

Use quadratic formula to solve x² = 4x.

Answer 1

Given,

x² = 4x

x² − 4x = 0

Comparing x² − 4x = 0 with ax² + bx + c = 0 we get,

a = 1, b = −4 and c = 0.

We know that,

x = `(−b ± sqrt(b^2−4ac))/(2a)`

Substituting values of a, b and c in above equation we get,

x = `(- (-4) ± sqrt((-4)^2−4(1)(0)))/(2(1))`

= `(4 +- sqrt(16 - 0))/2`

= `(4 +- 4)/2`

= `(4 + 4)/2` or `(4 - 4)/2`

= `8/2 or 0/2`

= 4 or 0