If a^3bc^2 < 0, which of the following must be correct? [Without calculator](A) a < 0 \& c < 0(B) b < 0 \& c < 0(C) a < 0 \& b > 0(D) a < 0 \& b > 0 or a > 0 \& b < 0
Q. If a3bc2<0, which of the following must be correct? [Without calculator](A) a<0&c<0(B) b<0&c<0(C) a<0&b>0(D) a<0&b>0 or a>0&b<0
Analyze Given Options: We know that a^3 \cdot b \cdot c^2 < 0. Since a3 and c2 are both raised to an even power, they will always be non-negative (zero or positive) regardless of the sign of a and c. Therefore, the sign of the expression is determined by the sign of b and the sign of a (since a negative number raised to an odd power is negative). If b is positive, then a must be negative for the expression to be negative. If b is negative, then a can be either positive or negative.
Option (A): Let's analyze the options given:(A) a < 0 & c < 0: This is not necessarily true because c could be positive and the expression could still be negative as long as a is negative and b is positive.
Option (B): (B) b < 0 & c < 0: This is not necessarily true because c could be positive and the expression could still be negative as long as a is negative and b is positive.
Option (C):C a < 0 & b > 0: This could be true because if a is negative and raised to an odd power, it remains negative, and if b is positive, the expression would be negative. However, this does not cover all cases because b could also be negative.
Option (D): (D) a < 0 \& b > 0 or a > 0 \& b < 0: This must be correct because it covers all cases where the expression could be negative. If a is negative and b is positive, the expression is negative. If a is positive and b is negative, the expression is also negative. This option accounts for the fact that the sign of a3 is determined by the sign of a, and the overall sign of the expression is determined by the sign of b.
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