Sqrt(2*0,4*a) >= 160
0,8*a >= 25600
<span>a >= 32000 </span>
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1) 3x-(7x-2*=18
3x-7x+2=18
-4x+2=18
-4x=18-2
-4x=16
x=4
2) <span>7х-5(2х+1)=5х+19= пример с ошибкой.
3) </span><span> 6х\7=х-5\2 = 12x=7(x-5)=12x=7x-35=12x-7x=-35=5x=-35
x=-7
</span>
Х²-4х+4 = х²-2*2*х+2² = (х-2)² = (х-2)(х-2)