Question

Rob and Lila try to simplify 18 x 4² + (9 - 3)². Rob simplifies the expression and gets 360. Lila simplifies it and gets 324. Which student is correct? What error did the other student make?Please make it clear how Rob got his answer.

Answer 1

= 18 * $4^{2}$ + $6^{2}$          brackets first

= 18 * 16 + 36      next exponents

= 288 + 36           then multiplication

= 324                   finally addition

Lisa was right, she used BEDMAS properly while Rob treated the $(9 - 3)^{2}$ as ($9^{2}$ - $3^{2}$). This made it 18 * 16 + (81 - 9) = 288 + 72 = 360.