Explanation
[tex]7(x-4)+28[/tex]
Step 1
use distributive property
[tex]\text{remember: a(b+c)=ab+ac}[/tex]then
[tex]\begin{gathered} 7(x-4)+28 \\ 7x-(7)(4)+28 \\ 7x-28+28 \end{gathered}[/tex]Step 2
Add similar terms
[tex]\begin{gathered} 7x-28+28 \\ 7x-0 \end{gathered}[/tex]Step 3
when you have an expression, there is no change if you add cero, or substrate cero, no need to write it, then
[tex]\begin{gathered} 7x-0 \\ 7x \end{gathered}[/tex]