Answer:
5(2x + 4) = 10(x + 2)
Explanation:
An equation has infinitely many solutions when they end in 0 = 0, that is, both sides are exactly equivalent. In this case, basically, all real numbers are solution, it's like a line under the same line, it's like the reflexive property, every number is equal to itself.
The expression that fulfil that definition is the second one, because:
5(2x + 4) = 10(x + 2)
10x + 20 = 10x + 20
10x - 10x = 20 - 20x
0 = 0
Therefore, it's demonstrated that the second equation has infinite solutions, that is, all numbers are solutions.