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x2−20x+51=0

x1+x2 x1⋅x2 x1 х2

x2-9x-52=0


x1+x2 x1⋅x2 x1 х2

x1 + x2 = -b
x1 * x2  = c

x1 + x2 = 20  x1= 17 x2 = 3
x1 * x2  = 51  

x1 + x2 = - b
x1 * x2 = c

x1 + x2 = 9
x1 * x2 = -52  x1=13 x2=-4