Answer:

Explanation:
The complete exercise is: "What algebraic expression must be subtracted from the sum of
and
to give
as the result?"
For this exercise it is necessary to remember that a sum is the result of an addition. Then, if you need to find the sum of
and
, you need to add them by combining the like terms.
You also need to remember the multiplication of signs:

So, you get that the sum of those expression is the following:

Since you must find the algebraic expression asked in the exercise, you need to subtract the expression
from that sum calculated above.
Therefore, you get:

Then, the algebraic expression asked is:
