GRE Subject Test: Math : Solving Inequalities

Study concepts, example questions & explanations for GRE Subject Test: Math

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Example Questions

Example Question #31 : Classifying Algebraic Functions

\(\displaystyle -12 > z-4\)

Possible Answers:

\(\displaystyle z\leq -8\)

\(\displaystyle z< -8\)

\(\displaystyle z> -8\)

\(\displaystyle z\geq -8\)

Correct answer:

\(\displaystyle z< -8\)

Explanation:

\(\displaystyle -12 > z-4\)

Add 4 to both sides of the inequality.

\(\displaystyle -12 + 4> z-4 + 4\)

\(\displaystyle -8 > z\)

Because the variable \(\displaystyle z\) is to the right of the inequality, it needs to be placed to the left of the inequality. When this happens, the inequality sign needs to be switched to its opposite.

\(\displaystyle z < -8\)

 

Example Question #31 : Classifying Algebraic Functions

\(\displaystyle 3x +6\geq -2x + 8\)

Possible Answers:

\(\displaystyle x\geq \frac{5}{2}\)

\(\displaystyle x\leq \frac{2}{5}\)

\(\displaystyle x\geq \frac{2}{5}\)

\(\displaystyle x\leq \frac{5}{2}\)

Correct answer:

\(\displaystyle x\geq \frac{2}{5}\)

Explanation:

\(\displaystyle 3x + 6 \geq -2x + 8\)

Subtract 6 from both sides of the inequality.

\(\displaystyle 3x + 6 - 6\geq -2x + 8 - 6\)

\(\displaystyle 3x\geq -2x + 2\)

Add \(\displaystyle 2x\) to both sides of the inequality.

\(\displaystyle 3x + 2x\geq -2x + 2x + 2\)

\(\displaystyle 5x \geq 2\) 

Divide both sides by \(\displaystyle 5\).

\(\displaystyle \frac{5x}{5} \geq \frac{2}{5}\)

\(\displaystyle x\geq \frac{2}{5}\)

Example Question #11 : Solving Inequalities

The difference between a number and 6 is no more than 7. What would those numbers be?

Possible Answers:

\(\displaystyle n\leq 13\)

\(\displaystyle n\leq 6\)

\(\displaystyle n\geq 13\)

\(\displaystyle n\leq 7\)

Correct answer:

\(\displaystyle n\leq 13\)

Explanation:

\(\displaystyle n - 6\leq 7\)

Would be the inequality that represents that statement.

Add \(\displaystyle 6\) to both sides of that inequality.

\(\displaystyle n - 6 + 6 \leq 13\)

\(\displaystyle n\leq 13\)

Example Question #12 : Solving Inequalities

\(\displaystyle x^{2} -64< 0\)  Find the solution set.

Possible Answers:

\(\displaystyle x < 8\)

\(\displaystyle -8< x< 8\)

\(\displaystyle 8< x< 8\)

\(\displaystyle x = 0\)

Correct answer:

\(\displaystyle -8< x< 8\)

Explanation:

\(\displaystyle x^{2} - 64< 0\)

\(\displaystyle x^{2} < 64\)

\(\displaystyle -8 < x < 8\)

Example Question #13 : Inequalities

\(\displaystyle 3 (x-3) > 4 (x+2)\)

Possible Answers:

\(\displaystyle x< 17\)

\(\displaystyle x < -17\)

\(\displaystyle x< -1\)

\(\displaystyle x> -1\)

Correct answer:

\(\displaystyle x < -17\)

Explanation:

\(\displaystyle 3 (x-3) > 4(x+2)\)

Begin by simplifying the inequality by using the distributive property.

\(\displaystyle 3x - 9 > 4x +8\)

Add \(\displaystyle 9\) to both sides.

\(\displaystyle 3x-9 + 9 > 4x + 8 + 9\)

\(\displaystyle 3x> 4x + 17\)

Subtract \(\displaystyle 4x\) from both sides.

\(\displaystyle 3x-4x > 4x-4x+17\)

\(\displaystyle -x > 17\)

Because there is a negative variable, multiply both sides by \(\displaystyle -1\) and switch the inequality sign to its opposite.

\(\displaystyle x< -17\)

Example Question #13 : Solving Inequalities

\(\displaystyle b - 6 > 13\)

Possible Answers:

\(\displaystyle b > 19\)

\(\displaystyle b< 7\)

\(\displaystyle b> 7\)

\(\displaystyle b< 19\)

Correct answer:

\(\displaystyle b > 19\)

Explanation:

\(\displaystyle b - 6 > 13\)

Add 6 to both sides of the inequality.

\(\displaystyle b-6 + 6> 13 + 6\)

\(\displaystyle b> 19\)

Example Question #38 : Algebra

\(\displaystyle -3x -12> 15\)

Possible Answers:

\(\displaystyle x< 9\)

\(\displaystyle x\geq 9\)

\(\displaystyle x> -9\)

\(\displaystyle x < -9\)

Correct answer:

\(\displaystyle x < -9\)

Explanation:

\(\displaystyle -3x-12> 15\)

To isolate the variable, add \(\displaystyle 12\) to both sides of the inequality.

\(\displaystyle -3x-12+12 > 15 + 12\)

\(\displaystyle -3x >27\)

Divide both sides by \(\displaystyle -3.\) Because you are dividing by a negative integer, you have to flip or switch the inequality sign to its opposite.

\(\displaystyle x < -9\)

Example Question #14 : Solving Inequalities

Solve.

\(\displaystyle 12 + n \leq 4\)

Possible Answers:

\(\displaystyle n\leq -8\)

\(\displaystyle n\leq 8\)

\(\displaystyle n \leq -12\)

\(\displaystyle n\leq 12\)

Correct answer:

\(\displaystyle n\leq -8\)

Explanation:

\(\displaystyle 12+n\leq 4\)

To isolate the variable , subtract \(\displaystyle 12\) from both sides of the inequality.

\(\displaystyle (12-12) + n \leq4-12\)

\(\displaystyle n\leq -8\)

Example Question #15 : Solving Inequalities

\(\displaystyle x + 0.8\leq -0.5\)

Possible Answers:

\(\displaystyle x\leq 1.3\)

\(\displaystyle x\leq 0.3\)

\(\displaystyle x\leq -1.3\)

\(\displaystyle x\leq -0.3\)

Correct answer:

\(\displaystyle x\leq -1.3\)

Explanation:

\(\displaystyle x + 0.8\leq -0.5\)

To isolate the variable, subtract \(\displaystyle 0.8\) from both sides of the inequality.

\(\displaystyle x + 0.8-0.8 \leq -0.5-0.8\)

\(\displaystyle x\leq -1.3\)

Example Question #16 : Solving Inequalities

\(\displaystyle 8x-10 > 4x - 6\)

Possible Answers:

\(\displaystyle x> -1\)

\(\displaystyle x>3\)

\(\displaystyle x< 3\)

\(\displaystyle x>1\)

Correct answer:

\(\displaystyle x>1\)

Explanation:

\(\displaystyle 8x-10 > 4x-6\)

Subtract \(\displaystyle 4x\) from both sides of the equation

\(\displaystyle 8x-4x-10 > 4x-4x-6\)

\(\displaystyle 4x -10> -6\)

Add \(\displaystyle 10\) to both sides of the equation.

\(\displaystyle 4x-10 + 10 = -6 + 10\)

\(\displaystyle 4x > 4\)

Divide both sides by 4.

\(\displaystyle \frac{4x}{4} >\frac{4}{4}\)

\(\displaystyle x>1\)

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