Сократите дробь 5a^2+19a-4
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1-25a^2 2

5a^2+19a-4=0D=19^2 + 4×5×4 = 361 + 80 = 441 = 21a1=-19+21/2×5 =- 0,2a2=-19-11/2×5 = 30/10= 31-25×0,04×2=-11-25×9×2=-449