202211041443 Solution to 1978-CE-AMATH-I-1

Find the range of $x$ satisfying the inequality

$(x-2)(x+3)<2(x-2)$ .

Roughwork.

$\begin{aligned} (x-2)(x+3) & <2(x-2) \\ x^2+x-6 & < 2x-4 \\ x^2-x-2 & < 0 \\ (x-2)(x+1) & < 0 \\ -2<x & <1 \\ \end{aligned}$

$\therefore$ The range of $x$ is $x\in (-2,1)$ .

物理後生﹑掣數學之肘.
小子算數﹑指物理之月.