Question

已知5x²-3x-5=0，則5x²-2x-

1

5x2-2x-5

=______．

Answer 1

5x²-2x-

1

5x2-2x-5

=x+5-

1

x

，
∵5x²-3x=5，兩邊同除以5x得：x-

1

x

=

3

5

，
∴原式=x+5-

1

x

=

28

5

．