<span>(m+3)^2+(3m-1)(3m+1) = </span>(m+3)^2+(9m-1)²
3х^2 + bx - 72 = 0
X1 = 8
3•64 + 8b - 72 = 0
8b = 72 - 192
b = - 120 : 8
b = - 15
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3x^2 - 15x - 72 = 0
3( x^2 - 5x - 24 ) = 0
D = 25 + 96 = 121 = 11^2
X1 = ( 5 + 11 ) : 2 = 8
X2 = ( 5 - 11 ) : 2 = - 3
Волооот...................
6·(2/3) - 8(5/8) = 12/3 - 40/8 = 4 - 5 = -1