How do you solve the inequality 9 - x > 10?

Dec 27, 2015

$x < - 1$

Explanation:

You first substract 9 at both sides. So $9 - x > 10 \iff - x > 1$. You then multiply both sides by $- 1$ in order to have the inequality for $x$. Be careful, opposites and quotients change the direction of an inequality!

So $- x > 1 \iff \left(- 1\right) \cdot \left(- x\right) < - 1 \iff x < 1$

Dec 27, 2015

Isolate x to solve the inequality

Explanation:

9 - x > 10
-x > 1
x < -1 *

*Always flip the inequality sign's direction when dividing the constant term on one side by a negative coefficient of x.

The answer is x < -1

Have a good day!