First, rewrite the equation \(2x^2 - 10x + 8 = kx\) as a standard quadratic equation:
\(2x^2 - (10 + k)x + 8 = 0\).
For the quadratic equation \(ax^2 + bx + c = 0\) to have no real roots, the discriminant must be less than zero:
\(b^2 - 4ac < 0\).
Here, \(a = 2\), \(b = -(10 + k)\), and \(c = 8\).
Calculate the discriminant:
\((-(10 + k))^2 - 4 \times 2 \times 8 < 0\)
\((10 + k)^2 - 64 < 0\)
\(100 + 20k + k^2 - 64 < 0\)
\(k^2 + 20k + 36 < 0\).
To find the values of \(k\), solve the inequality:
Factor the quadratic:
\((k + 18)(k + 2) < 0\).
The critical points are \(k = -18\) and \(k = -2\).
Test intervals around these points to determine where the inequality holds:
- For \(k < -18\), both factors are negative, so the product is positive.
- For \(-18 < k < -2\), one factor is negative and the other is positive, so the product is negative.
- For \(k > -2\), both factors are positive, so the product is positive.
Thus, the solution is \(-18 < k < -2\).