6) (1(2)/(7))^x^(2-4)leqslant 1

To solve the inequality \((1\frac{2}{7})^{x^2 - 4} \leq 1\), we first need to express the mixed number as an improper fraction. So the inequality becomes: Next, we analyze the expression \(\left(\frac{9}{7}\right)^{x^2 - 4}\). For this expression to be less than or equal to 1, the exponent must be less than or equal to 0 because . Solving this quadratic inequality: This gives us: Therefore, the solution to the inequality \((1\frac{2}{7})^{x^2 - 4} \leq 1\) is: