Question

Determine x^2-x-20=x^2 is quadratic equation or not ?why?

Answer 1

${x}^{2} - x - 20 = {x}^{2}$

$lhs = {x}^{2} - x - 20$

$rhs = {x}^{2}$

$does \: lhs = rhs$

${x}^{2} - x - 20 = {x}^{2}$

$x - 20 = {x}^{2}$

$20 = {x}^{2} - x$

$x = 20$