Simplify the following expressions:
$(2+\sqrt{3})(2-\sqrt{3})$

$(2+\sqrt{3})(2-\sqrt{3})$

We know that $(a+b)(a-b)=a^2-b^2$

$(2+\sqrt{3})(2-\sqrt{3})$

$=(2{)}^2-(\sqrt{3}{)}^2$

$=4-3=1$