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Mathematics quadratic function in grade three (explanation)
f(x)=y=x^2-x+a

Because the parabolic opening is upward, and the function value can be less than 0.

So (-1) 2-4a >: 0

0 & lta & lt 1/4

f(m)=m^2-m+a<; 0

[ 1-√( 1-4a)]/2 & lt; m & lt[ 1+√( 1-4a)]/2

When x=[ 1-√( 1-4a)]/2

y=0,

So x < [1-√( 1-4a)]/2, y >;; 0

Because 0

So 0

So 0

1/2 & lt; [ 1+√( 1-4a)]/2 & lt; 1

So 0

So- 1

So f (m- 1) >: 0.

Choose B.