<p><span style="font-size:20px;"><span style="color:#8e44ad;">Deductions from the Given Information</span></span></p>
<p>The given information says that $(x-2y)(x+2y)=4$. If we FOIL this out, we get the following:</p>
<p style="text-align: center;">$$x^2-2yx+2yx-4y^2=4$$</p>
<p>which can be further simplified to...</p>
<p style="text-align: center;">$$x^2-4y^2=4$$</p>
<p><span style="color:#27ae60;"><span style="font-size:20px;">Solving the Problem</span></span></p>
<p><strong>Quantity A</strong> is equal to $x^2-4y^2$, which we determined to be equal to $4$ from our deductions of the given information.</p>
<p>In comparison with <strong>Quantity B</strong>, $8$, we can clearly see that<strong> <span style="color:#16a085;">Quantity B is larger</span></strong>.</p>