Let a, b and c be a real numbers such that a&gt;0,b&lt;0 and c&lt;0. Find the sign of each expression. a) -a b) bc c) a-b d) ab+ac

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Let a, b and c be a real numbers such that a&amp;gt;0,b&amp;lt;0 and c&amp;lt;0. Find the sign of each expression. a) -a b) bc c) a-b d) ab+ac

Malena · Accepted Answer

(a) Here a&amp;gt;0 ⇒ −a will be a negative number. Thus, sign of -a is negative . (b) It is known that product of two negative number will be positive. As b&amp;lt;0 and c&amp;lt;0 ⇒ bc&amp;gt;0. Thus, sign of bc is positive. (c) It is known that when a negative number is subtracted from a positive number, the resultant number will be positive. Here a&amp;gt;0,b&amp;lt;0 ⇒ a−b&amp;gt;0. Thus, sign of a-b is positive. (d) Here a&amp;gt;0,b&amp;lt;0 ⇒ ab&amp;lt;0 a&amp;gt;0,c&amp;lt;0 ⇒ ac&amp;lt;0 So ac and bc negative. It is known that sum of two negative number will be negative. Thus, ab+ac&amp;lt;0. Thus, sign of ab+ac is .

Let a, b and c be a real numbers such that a>0, b<0 and c<0. Find the sign of each expression.a) -ab) bcc) a-bd) ab+ac

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