(x-3)(x+7)-13=(x+8)(x-4)-2
x^2+7x-3x-21-13=x^2-4x+8x-32-2
x^2+4x-34=x^2+4x-34
0=0
x-любое
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Решение
<span>3.1<√10<3.2
</span>- 3,2 < - <span>√10 < - 3,1</span>
Ctg150·ctg60=ctg(180-30)·ctg60=-ctg30·ctg60=-1\√3·√3=-1
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