Question

Write as an algebraic expression and then simplify if possible: A number if that number and the number b sum to 40

Answer 1

40-b

Explanation:

this is correct because instead of putting 40-b=unknown number you just make it into an expression

Answer 2

Let x be the unknown number.
x + b = 40

I think that's all the question asks for.

It could be written as x = 40 - b.
This can't be simplified.