a. \( \left(\frac{5}{3}\right)^{-1}-\sqrt{5^{-2}+0,45}+0,2^{2}= \)

First, let's simplify the expression step by step! For \( \left(\frac{5}{3}\right)^{-1} \), taking the reciprocal gives us \( \frac{3}{5} \). Next, we look at \( 5^{-2} + 0.45 \). Calculating \( 5^{-2} \) gives us \( \frac{1}{25} \) or \( 0.04 \), so we have \( 0.04 + 0.45 = 0.49 \) which is \( \sqrt{0.49} = 0.7 \). Now, finally, we compute \( 0.2^2 \) which is \( 0.04 \). Now putting it all together: - Start: \( \frac{3}{5} - 0.7 + 0.04 \). - \( \frac{3}{5} \) is \( 0.6 \), so we have \( 0.6 - 0.7 + 0.04 = -0.1 + 0.04 = -0.06 \). Thus, the final answer is \( -0.06 \).