Mathematics

Mathematics

Problem

Priya wants to verify whether x=−2x = -2 satisfies 5x+3=−75x + 3 = -7. She writes: 5(−2)+3=−10+3=−13=−75(-2) + 3 = -10 + 3 = -13 = -7. Hence, x=−2x = -2 is a solution. Which statement correctly explains the error in her verification? a) She multiplied 55 and −2-2 incorrectly; she thought 5×(−2)=−85\times(-2)=-8. b) She assumed that −13-13 and −7-7 are equal just because both numbers are negative. c) She added −10-10 and 33 incorrectly; it should be −7-7, not −13-13. d) She compared the left-hand side with the right-hand side before finishing the simplification of the left-hand side.

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