Answer:
C. -2b + 30 = 24
Step-by-step explanation:
[tex]METHOD\ \#1\\\\\text{Put b = 3 to each equation and check equality:}\\\\A.\ 3-24b=75\\L_s=3-24(3)=3-72=-69\\R_s=75\\L_s\neq R_s\\\\B.\ 65+9b=38\\L_s=65+9(3)=65+27=92\\R_s=38\\L_s\neq R_s\\\\C.\ -2b+30=24\\L_s=-2(3)+30=-6+30=24\\R_s=24\\L_s=R_s\\\\D.\ 102b-21=-55\\L_s=102(3)-21=306-21=285\\R_s=-55\\L_s\neq R_s[/tex]
[tex]METHOD\ \#2:\\\\\text{Solve each equation:}\\\\A.\\3-24b=75\qquad\text{subtract 3 from both sides}\\-24b=72\qquad\text{divide both sides by (-24)}\\b=-3\neq3\\\\B.\\65+9b=38\qquad\text{subtract 65 from both sides}\\9b=-27\qquad\text{divide both sides by 9}\\b=-3\neq3\\\\C.\\-2b+30=24\qquad\text{subtract 30 from both sides}\\-2b=-6\qquad\text{divide both sides by (-2)}\\b=3\\\\D.\\102b-21=-55\qquad\text{add 21 to both sides}\\102b=-34\qquad\text{divide both sides by 102}\\b=-\frac{1}{3}[/tex]
