X²/(x²+1)=z
(1+a)z²-3az+4a=0
D=9a²-16a(1+a)=9a²-16a-16a²=-7a²-16a
D≥0, -7a²-16a≥0
7a²+16a≤0
a(7a+16)≤0
1)a≥0 ∧ 7a+16≤0, a≥0 ∧ a≤-16/7 , a∈∅
2)a≤0 ∧ 7a+16≥0, a≤0 ∧ a≥-16/7, a∈/-16/7,0/
Otvet (-1/2,0/ pravilnyj...........
<span>(x+5)</span>²<span> + (x-2)</span>²<span> + (х-7)(x+7) = 11x+30
х</span>²+10х+25 + х² - 4х+4 + х²-49 = 11х+30
3х²-5х-50 = 0
D = 35-600
D<0
Уравнение не имеет решения
Х×14×10=280
140х=280
х=280÷140
х=2
163+37х+18х=328
163+55х=328
55х=328-163
55х=165
х=165÷55
х=3
(573+а)-173=617
573-173+а=617
400+а=617
а=617-400
а=217