<span>(25x²-29y²)² - (-24x²+20y²)²= [ формула разности квадратов a²-b²=(a-b)(a+b)]=
=(</span>(25x²-29y²) - (-24x²+20y²))<span><span> ·((25x²-29y²)+ (-24x²+20y²))=</span>
=(</span>25x²-29y² +24x²-20y²)·(<span>(25x²-29y² - 24x²+20y²)=</span>(49x²-49y²) · (x²-9y²)=
=49 (x-y)(x+y)(x-3y)(x+3y)
Корень из 121=11, 11^0=1. 11+1=12. 12 не кратно 11. Ответ: буква Е).
<span> [2x+38]=7
2x+38=7 x</span>₁<span>=-(31/2)
2x+38=-7 x</span>₂<span>=-(45/2)
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</span><span>
[2x-1]</span>≤<span>3
2x-1</span>≤3, 2x-1≥0
-(2x-1)≤3, 2x-1<0
x≤2, x≥1/2
x≥-1, x<1/2
x∈[1/2,2]
x∈[-1,1/2]
Точки пересечения и ответ:
x∈[-1,2]
1) х+у-(х+3у)=7+5
4у=12
у=3
х+3=7
х=4
2) 4х-у-(х+у)=3-6
3х=-3
х=-3
-3-у=6
у=6+3
у=9
3)у-х-(7у+х)=9+3
-6у=12
у=-2
-2-х=9
х=9+2
х=-11
5х+у-х+у=6+10
4х=16
х=4
4+у=-10
у=-10-4
у=-14