Dongcheng District, Beijing, 20 1 1, Grade Three, Second Model Mathematics, the seventh multiple-choice question! ! Detailed and accurate steps! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
From the hyperbola of the first and third quadrants, we can know that K-2 >; 0, then k>2. δ of another quadratic equation =-4k+5,
Using the property of inequality, both sides of k>2 are multiplied by -4 to get -4k.
So the equation has no real root, so choose a.