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Algebraic Inequalities Guide for the GMAT, GRE, SAT

Algebraic Inequalities 

Algebraic inequality statements are solved in the same manner as equations. However, do not forget that whenever you multiply or divide by a negative number, the order of the inequality, that is, the inequality symbol must be reversed. In reading the inequality symbol, remember that it points to the smaller quantity. is read is less than bis read is greater than b.

Example:

Solve for x: 12 – 4< 8

Solution:

Add –12 to each side.

–4
< –4

Divide by –4, remembering to reverse the inequality sign.
x>1

Example:

6+ 5 > 7+ 10

Solution:

Collect all the terms containing on the left side of the equation and all numerical terms on the right. As with equations, remember that if a term comes from one side of the inequality to the other, that term changes sign.

> 5

Divide (or multiply) by –1.
< –5




If < 0 and > 0, which of the following will always be greater than 0?
(A) x+y
(B) xy
(C)x/y
(D) xy
(E) –2x

E

The product of two negative numbers is positive.

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