1) <span>(7-2√3)(7+2√3) = 7^2-(2√3)^2=49-12=37</span>
<span>log3(x^2-11x+27)=2</span>
<span><span>log3(x^2-11x+27)=log3 9</span></span>
<span><span>(x^2-11x+27=9</span></span>
<span><span>x^2-11x+18=0</span></span>
<span><span>x1=9</span></span>
<span><span>x2=2</span></span>
10х+21-6х=13+2х
4х-2х=13-21
2х=-8
х=-4