Remember to treat the sum as a single quantity when multiplying.
8(a+b)
The key word is ...times... This indicates that we should multiply two things.
... * ...
The two terms that we are multiplying are: eight and the sum of a and b. Eight has to be expressed as a number.
8* the sum ofaandb
Now, let's algebraically express the right-hand side of the multiplication. We have to remember to treat it as a single quantity.
eight times the sum of aandb
8*( a + b)
In this case we can rewrite this expression.
8* (a+b) ⇔ 8(a+b)
Note that this is only one of multiple ways to algebraically express the given verbal expression.