Question

alguém consegue resolver a equação da letra f?

Answer 1

                  $\left(\dfrac{2}{5}\right)^{x+3}=\left(\dfrac{5^3}{2^3}\right)^{x-1}\cdot \left(\dfrac{2}{5}\right)^{2x-3}\\ \\ \\ \left(\dfrac{2}{5}\right)^{x+3}=\left(\dfrac{5}{2}\right)^{3x-3}\cdot \left(\dfrac{2}{5}\right)^{2x-3}\\ \\ \\ \left(\dfrac{2}{5}\right)^{x+3}=\left(\dfrac{2}{5}\right)^{-x}\\ \\ \\ x+3=-x\\ \\ 2x = -3\\ \\ \boxed{\boxed{x=-\dfrac{3}{2}}}$