Question

Four less than a number equals four times the sum of a number and 2. Is this statement true for only one number, for all numbers, or for no numbers? Explain your reasoning.

Answer 1

If the same number is indicated in both places where the words "a number"
appear, then the statement is true only when that number is -4 .

If "a number" and "a number" stand for two different numbers, then
there are an infinite list of ordered pairs of numbers that make the
statement true.