Question

Using graph $y=x^2$, solve the equation $x^2-x-2=0$.

Answer 1

Solution:

The roots of the equation $x^2-x-2=0$ are the $x$-coordinates of the points of the intersection of the parabola $y^2=x$ and the straight line $y=x+2.$

Consider $y=x^2$

$x$	$0$	$2$	$3$	$4$	$-1$	$-2$	$-3$	$-4$
$y$	$0$	$4$	$9$	$16$	$1$	$4$	$9$	$16$

Consider $y=x+2$

$x$	$0$	$-2$
$y$	$2$	$0$

Hence, the solution set is $\{-1,2\}.$