The second description is not suitable.
It should be "simplify the terms" sice you are just adding 36 and -20.
Consider the given expression,
[tex]3\mleft(9u+12\mright)-16=20[/tex]
Apply the distributive property,
[tex]\begin{gathered} 3(9u)+3(12)-16=20 \\ 27u+36-16=20 \end{gathered}[/tex]
Combine like terms,
[tex]27u+20=20[/tex]
Subtract 20 from both sides,
[tex]27u=0[/tex]
Divide both sides by 27,
[tex]u=0[/tex]
