Find the values of k for which the equation (k-1)x²+kx-k = 0 has real and distinct roots.
- Find the values of k for which the equation (k-1)x²+kx-k = 0 has real and distinct roots.[4]
Mark scheme
Marking points from the official mark scheme (May/June 2019). The mark or mark type is shown in brackets.
- [B1] k² - 4(k-1)(-k) oe
- [M1] k(5k-4)
- [A1] Correct critical values 0, 0.8 oe
- [A1] FT their critical values provided their ak² + bk + c > 0 has positive a and there are 2 values; mark final answer. If B1 M0 allow SC1 for a final answer of k > 0.8 oe
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