Question 835237
*[tex \Large 3x^2 - 7x + 6 \le 0]

The zeros of the LHS occur at *[tex \Large x = \frac{7 \pm \sqrt{49 - 4(3)(6)}}{2}], which are non-real, so *[tex \Large f(x) = 3x^2 - 7x + 6] doesn't cross the x-axis. Since it is continuous, it is either positive everywhere or negative everywhere. Clearly it must be positive everywhere (check by substituting a large value of x), so it can never be negative. There are no solutions.