6a^2-10a-a^2-7a-3a-21=5a^2-20a-21
64х²-9+48х-64х²-87=0
48х-96=0
48х=96
х=2
Cos33°⋅cos9°+sin33°⋅sin9°=cos(33°-9°)=cos24°
(5х-2)(х+1)-(5-2x)^25x^2+5x-2x-2-25+20x-4x^2=x^2+23x-27
<span>4х2-7х+а=0</span>
<span>4х2/4-7/4=a/4</span>
<span>Х2-7/4+а=0</span>
<span>Х1=0,75</span>
<span>Х1+х2=7/4</span>
<span>Х1* х2=а/4</span><span>
х2=1(1.75-0,75)
а/4=1/4=0,25
Ответ:1; 0,25
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