[latex] left { {{1- frac{26-x}{42-x- x^{2} } geq 0} atop {42-x- x^{2} } eq 0} ight. (42-x- x^{2} -26+x)/(42-x- x^{2} ) geq 0 (x+7)(6-x) eq 0 ( x^{2} -16)/((x+7)(x-6)) geq 0 [/latex]x∈(-∞;-7)∪[-4;4]∪(6;+∞)