9. \( 2.8 k-11=45 \)

To solve the equation \( 2.8k - 11 = 45 \), we’ll start by isolating the term with \( k \). Add 11 to both sides: \( 2.8k = 56 \). Next, divide each side by 2.8 to find \( k \): \( k = \frac{56}{2.8} = 20 \). So, \( k \) equals 20! To verify, plug \( k \) back into the original equation: \( 2.8(20) - 11 = 45\). Simplifying, \( 56 - 11 = 45 \), confirming that our solution is correct.