SAT Math : How to find the solution to an inequality with addition

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #2 : Inequalities

What values of x make the following statement true?

|x – 3| < 9

Possible Answers:

–6 < x < 12

–3 < x < 9

6 < x < 12

x < 12

–12 < x < 6

Correct answer:

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

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

Possible Answers:

w/2

|w|

3w/2

|w|0.5

w2

Correct answer:

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 .

Possible Answers:

Correct answer:

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

What values of  make the statement  true?

Possible Answers:

Correct answer:

Explanation:

First, solve the inequality :

Since we are dealing with absolute value,  must also be true; therefore:

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

Solve:  

Possible Answers:

Correct answer:

Explanation:

To solve , isolate .

Divide by three on both sides.

Example Question #21 : Inequalities

Solve for .

Possible Answers:

Correct answer:

Explanation:

We want to isolate the variable on one side and numbers on another side. Treat like a normal equation. 

 Subtract  on both sides.

 Divide  on both sides. Remember to flip the sign.

Example Question #5 : How To Find The Solution To An Inequality With Addition

Solve for .

Possible Answers:

Correct answer:

Explanation:

We want to isolate the variable on one side and numbers on another side. Treat like a normal equation. 

 Subtract  on both sides.

Example Question #6 : How To Find The Solution To An Inequality With Addition

Solve for .

Possible Answers:

Correct answer:

Explanation:

We want to isolate the variable on one side and numbers on another side. Treat like a normal equation. 

 We need to set-up two equations since its absolute value.

 Subtract  on both sides. 

 Divide  on both sides which flips the sign.

 Subtract  on both sides. 

Since we have the 's being either greater than or less than the values, we can combine them to get .

Example Question #23 : Inequalities

Solve for .

Possible Answers:

Correct answer:

Explanation:

We want to isolate the variable on one side and numbers on another side. Treat like a normal equation. 

 We need to set-up two equations since it's absolute value.

 Subtract  on both sides.

 Divide  on both sides.

 Distribute the negative sign to each term in the parenthesis.

 Add  and subtract  on both sides.

 Divide  on both sides.

 We must check each answer. Let's try .

     This is true therefore  is a correct answer. Let's next try .

   This is not true therefore  is not correct. 

Final answer is just .

Example Question #15 : New Sat Math Calculator

If x+1< 4 and y-2<-1 , then which of the following could be the value of ?

Possible Answers:

Correct answer:

Explanation:

To solve this problem, add the two equations together:

x+1<4

y-2<-1

x+1+y-2<4-1

x+y-1<3

x+y<4

The only answer choice that satisfies this equation is 0, because 0 is less than 4.

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