What is wrong with the following "proof" that −3 = 3, using backward reasoning? Assume that −3 = 3. Squaring both sides yields $( - 3 ) ^ { 2 } = 3 ^ { 2 } \text {, or } 9 = 9 \text {. Therefore } - 3 = 3 \text {. }$

Question

Quizplus · Accepted Answer

The Answer of What is wrong with the following "proof" that −3 = 3, using backward reasoning? Assume that −3 = 3. Squaring both sides yields $( - 3 ) ^ { 2 } = 3 ^ { 2 } \text {, or } 9 = 9 \text {. Therefore } - 3 = 3 \text {. }$

What Is Wrong with the Following "Proof" That −3 = (−3)2=32, or 9=9. Therefore −3=3. ( - 3 ) ^ { 2 } = 3 ^ { 2 } \text {, or } 9 = 9 \text {. Therefore } - 3 = 3 \text {. }(−3)2=32, or 9=9. Therefore −3=3.

What Is Wrong with the Following "Proof" That −3 = $( - 3 ) ^ { 2 } = 3 ^ { 2 } \text {, or } 9 = 9 \text {. Therefore } - 3 = 3 \text {. }$