The question states that the algebraic expression is a perfect square. We will use the inspection method (trial-and-error) method to factorize the expression..

Both expression above are the same as it is a perfect square. Create an equation using the same technique used to check if the factorization is correct

$\displaystyle x\left( {{{a}^{2}}-5} \right)=-4x\ \text{and }x\left( {{{a}^{2}}-5} \right)=-4x$

$\displaystyle {{a}^{2}}-5=-4$

$\displaystyle {{a}^{2}}=-4+5$

$\displaystyle a=\sqrt{1}$

$\displaystyle a=\pm 1$

Small Group Tuition Additional Math (A Math) at Woodlands, Elementary Math (E Math) Singapore Syllabus at Admiralty, Woodlands and johor Bahru.