# PSAT Math : How to find the solution to an inequality with addition

## Example Questions

### Example Question #11 : Inequalities

What values of x make the following statement true?

|x – 3| < 9

x < 12

–3 < x < 9

–6 < x < 12

6 < x < 12

–12 < x < 6

–6 < x < 12

Explanation:

Solve the inequality by adding 3 to both sides to get x < 12.  Since it is absolute value, x – 3 > –9 must also be solved by adding 3 to both sides so: x > –6 so combined.

### Example Question #12 : Inequalities

If –1 < w < 1, all of the following must also be greater than –1 and less than 1 EXCEPT for which choice?

w/2

|w|0.5

w2

3w/2

|w|

3w/2

Explanation:

3w/2 will become greater than 1 as soon as w is greater than two thirds. It will likewise become less than –1 as soon as w is less than negative two thirds. All the other options always return values between –1 and 1.

### Example Question #2 : How To Find The Solution To An Inequality With Addition

Solve for .       Explanation:

Absolute value problems always have two sides: one positive and one negative.

First, take the problem as is and drop the absolute value signs for the positive side: z – 3 ≥ 5. When the original inequality is multiplied by –1 we get z – 3 ≤ –5.

Solve each inequality separately to get z ≤ –2 or z ≥ 8 (the inequality sign flips when multiplying or dividing by a negative number).

We can verify the solution by substituting in 0 for z to see if we get a true or false statement. Since –3 ≥ 5 is always false we know we want the two outside inequalities, rather than their intersection.

### Example Question #1 : How To Find The Solution To An Inequality With Addition

If and , then what is the value of ?      Explanation:

To solve this problem, add the two equations together:     The only answer choice that satisfies this equation is 0, because 0 is less than 4.

### Example Question #51 : Equations / Inequalities

If , which of the following could be a value of ?

-      Explanation:

In order to solve this inequality, you must isolate on one side of the equation.   Therefore, the only option that solves the inequality is ### Example Question #2 : How To Find The Solution To An Inequality With Addition

What values of make the statement true?      Explanation:

First, solve the inequality :   Since we are dealing with absolute value, must also be true; therefore:   ### All PSAT Math Resources 