[mathjax] This question was extracted from Nan Hua High School Sec 4 A Maths Mid year Exam 2018. Remember the use of algebraic expansion in sec 2 whereby [latex](a+b)^2[/latex] where most students will just expand it as [latex](a+b)(a+b)[/latex]. The truth is that students are expected to memorise [latex](a\pm b)^2 = a^2 \pm 2ab + b^2[/latex] to […]