Question

Solve graphically.

Express answers in both inequality and interval notation.

$x^2+21>10x$

Answer 1

$x^2+21>10x$

$x^2-10x+21>0$

$(x-3)(x-7)>0$

	x<3	x=3	3<x<7	x=7	x>7
x-7	-	-	-	0	+
x-3	-	0	+	+	+
(x-7)(x-3)	+	0	-	0	+

$x<3,x>7$

Interval notation $(-\infty ,3)\cup (7,\infty )$