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(3x+y)(x+y)-4 (x-y)=3x2+3xy+xy+y2-4xy+4y2=3x2+4xy-4xy+5y2=3x2+5y2.
Решение
<span>3x^{4} - 13x^{2}+4=0
</span>x² = t, t ≥ 0
3t² - 13t + 4 = 0
D = 169 - 4*3*4 = 121
t1 = (13 - 11)/6
t1 = 1/3
t2 = (13 + 11)/6
t2 = 4
1) x² = 1/3
x1 = - √3/3
x2 = √3/3
2) x² = 4
x3 = - 2
x4 = 2
16(5k-11)^2-100K^2=
(4(5k-11)-10k)(4(5k-11)+10k)=
(20k-44-10k)(20k-44+10k)=
(10k-44)(30k-44)