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1) <span>12x²y+3xy=3ху(4х+1)
2) </span><span>(х-9)(х-3)-(х-8)(х+8)=-5
х</span>²-3х-9х+27-(х²-64)=-5
х²-3х-9х+27-х²+64+5=0
-12х+96=0
-12х=-96
х=8
3) <span>{4х-7у=1
</span><span>{2х+7у=11
</span>6х=12
х=2
4+7у=11
7у=7
у=1
5) ⇒ x² +x=0
x(x+1) =0
a) x=0
b) x= -1
8) 3^(x-1) + 3·3^(x-1) + 3²·3^(x-1) = 13·3^(x² -7)
3^(x-1)·(1+3+9)) = 13·3^(x² -7)
3^(x-1) = 3^(x² -7)
3^(x-1)· {1- 3^[x² -7 - (x-1)]} = 0
3^(x-1) ≠ 0 ⇒
3^(x²-x -6) =1 ⇒
x² -x - 6 = 0
(x -3)(x+2) = 0 ⇒ x1 = 3
x2 = -2
4x²-2x⁶+5x⁶-3x²+44-3x⁶=20;
x⁶(5-2-3)+x²(4-3)+44=20;
x⁶*0+x²=-24;
x²=-24;
x²≠-24 ⇒ Ответ: нет решений(3 вариант);