Question

Check whether the following is quadratic equation.
$(x-2)(x+1)=(x-1)(x+3)$

Answer 1

$(x-2)(x+1)=(x-1)(x+3)$

$\Rightarrow x(x+1)-2(x+1)=x(x+3)-1(x+3)$

$\Rightarrow x^2-x-2=x^2+2x-3$

$\Rightarrow -2+3=2x+x$

$\Rightarrow x=1$

As, the algebraic expression is not of the form $a{x}^2+bx+c$, therefore, it is not a quadratic equation.