I uploaded it here as the answers Bc
Slkwowkneojw
Answer: 23
When using multiplication with brackets, you multiply the number by all the numbers within the bracket before adding them together.
Therefore when it is 8(7 + 23) it basically means: 8(7) + 8(23)
It is a straight line of symmetry because if you have a paper A and you fold it, it will form a straight line, and that is also meaning a straight line of symmetry. If you fold it any other way, it will not be a line of symmetry.
Hope this helps you ;)