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G(x^2 - x) = 1 - lg5
<span>lg(x^2 - x) = lg10 - lg5 = lg(10/5) = lg2 </span>
<span>x^2 - x = 2 </span>
<span>два решения, x = -1 и x = 2</span>
<span>X^2+11x-21=0
D=11*11+4*21=205
x12=(-11+-</span>√205<span>)/2
x=(-11+</span>√205)/2
x=(-11-√205)/2