Question

25 la puterea -x+2 mai mic sau egal cu 1 pe 5
cum o pot rezolva?

Answer 1

$25^{-x+2}\leqslant\dfrac{1}{5},\ sau\ (5^{2})^{2-x}\leqslant5^{-1},\ sau\ 5^{4-2x}\leqslant 5^{-1}\Rightarrow\\\\\Rightarrow 4-2x\leqslant -1\Rightarrow 2x\geqslant 5,\ deci\ x\in\left[\dfrac{5}2,\ +\infty\right ).$

Green eyes.