I don’t understand stand this question someone please help me with work shown

Answer:
• If M is a midpoint of AB, then AM = MB
[tex](4s + 4) = (2s + 6)[/tex]
• collect like terms together:
[tex]→ \: 4s - 2s = 6 - 4 \\ \\ →2s = 2 \\ \\ → \: { \boxed{ \boxed{ \: \: s = 1 \: \: }}}[/tex]