Viết biểu thức <span class="MathJax_Preview" style="color: inherit;"><span class="MJXp-math" id="MJXp-Span-1"><span class="MJXp-mstyle" id="MJXp-Span-2"><span class="MJXp-mo" id="MJXp-Span-3" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-4">x</span><span class="MJXp-mo" id="MJXp-Span-5" style="margin-left: 0.267em; margin-right: 0.267em;">−</span><span class="MJXp-mn" id="MJXp-Span-6">3</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-7">y</span><span class="MJXp-mo" id="MJXp-Span-8" style="margin-left: 0em; margin-right: 0em;">)</span><span class="MJXp-mo" id="MJXp-Span-9" style="margin-left: 0em; margin-right: 0em;">(</span><span class="MJXp-msubsup" id="MJXp-Span-10"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-11" style="margin-right: 0.05em;">x</span><span class="MJXp-mn MJXp-script" id="MJXp-Span-12" style="vertical-align: 0.5em;">2</span></span><span class="MJXp-mo" id="MJXp-Span-13" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-mn" id="MJXp-Span-14">3</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-15">x</span><span class="MJXp-mi MJXp-italic" id="MJXp-Span-16">y</span><span class="MJXp-mo" id="MJXp-Span-17" style="margin-left: 0.267em; margin-right: 0.267em;">+</span><span class="MJXp-mn" id="MJXp-Span-18">9</span><span class="MJXp-msubsup" id="MJXp-Span-19"><span class="MJXp-mi MJXp-italic" id="MJXp-Span-20" style="margin-right: 0.05em;">y</span><span class="MJXp-mn MJXp-script" id="MJXp-Span-21" style="vertical-align: 0.5em;">2</span></span><span class="MJXp-mo" id="MJXp-Span-22" style="margin-left: 0em; margin-right: 0em;">)</span></span></span></span><script type="math/tex" id="MathJax-Element-1">\Large (x-3y)(x^2+3xy+9y^2)</script> dưới dạng hiệu hai lập