Let's simplify step-by-step.23.6−7.1a−4.2b−(5.8b−9a)Distribute the Negative Sign:=23.6−7.1a−4.2b+−1(5.8b−9a)=23.6+−7.1a+−4.2b+−1(5.8b)+−1(−9a)=23.6+−7.1a+−4.2b+−5.8b+9aCombine Like Terms:=23.6+−7.1a+−4.2b+−5.8b+9a=(−7.1a+9a)+(−4.2b+−5.8b)+(23.6)=1.9a+−10b+23.6