( 2x - 1 ) ^2 - 5 = 4x^2 - 3(X - 1 ) ;
4x^2 - 4x + 1 - 5 = 4x^2 - 3x + 3 ;
- 4x + 3x = 3 + 4 ;
X = 7
9х^2-24ху+16^2
m^2-36
64b^2-25a^2
B1 = ¼; q = 1/2; bn = 1/512
Sn - ?
bn = b1 * q^(n-1) => q^(n-1) = bn/b1
q^(n-1) = 1/128
1/2^(n-1) = (1/2)^7
n - 1 = 7
n = 8
Sn = b1 * (qⁿ - 1)/(q - 1) = 1/4 * (1/256 - 1)/(1/2 - 1) = 1/4 * 2*255/256 = 255/512
Ответ: 255/512
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