-3x^2+6x-1+10+2x*(x-5)+7x^2=3
-3x^2+6x-1+10+2x^2-10x+ 7x^2=3
6x^2-4x+9=3
ОТВЕТ:-17;0;-25,3
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25-10х+х^2=0
х^2-10х+25=0
(х-5)^2=0
х-5=0
х=5
2)(2n²+11n+14)/(n+3) - 2n + 1/(n+3)=(2n²+11n+15)/(n+3) -2n=
=(2n²+11n+15-2n²-6n)/(n+3)=(5n+15)/(n+3)=
=5(n+3)/(n+3)=5, n≠-3
4)3ˇ(10x+5)-1≥0
3ˇ(10x+5)≥1
3ˇ(10x+5)≥3ˇ0
10x+5≥0
10x≥-5
x≥-1/2
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