Bn=b1*q^n-1
b8= -18 * 1/2^8-1= -18*1/2^7= -18*1/128=-1/128=-9/64
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12=2²*3
<span> 3x - y + 10 = 0
-2x + y - 7 = 0
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y = 3x + 10
y = 2x + 7
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3x + 10 = 2x + 7
3x - 2x = 7 - 10
x = - 3
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y = 2*( - 3 ) + 7 = - 6 + 7 = 1
Ответ ( - 3 ; 1 )
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