Question

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

Answer 1

`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 (-1)*(-x) < -1 iff x < 1`

Answer 2

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!