= 5-a²+25+a² / 5a = 30/5a = 6/a = 6 : 1/3 = 6*3=18
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б)<span> ℓog2x+3(5x2+11x+3)=2</span>
<span>5x²+11x+3=(2x+3)²</span>
<span>5x²+11x+3=4x²+12x+9</span>
<span>5x²+11x+3-4x²-12x-9=0</span>
<span>x²-x-6=0</span>
<span>D = 1²-4*1*(-6)=1+24=25</span>
<span>x1=(1+5)/2=3</span>
<span>x2=(1-5)/2=-2</span>
(3 + a)x = 14
x = 14/(3 + a)
а) x = 7
7 = 14/(3 + a)
1 = 2/(3 + a)
3 + a = 2
a = -1
б) Уравнение не будет корней, когда знаменатель дроби 14/(3 + a) равен нулю:
3 + a = 0
a = -3
Ответ: а) при а = -1; б) при а = -2.