Question

Let ∑ = {0,1, 2, 3, 4, 5, 6, 7, 8, 9, +, =} and consider the language L of all strings over ∑ that constitute a valid equation of the form a + b = c where a, b, and c are non-negative integers represented in base 10, without leading zeros. Some elements of L include 13 + 17 = 30 and 90 + 0 = 90, but not 13 + 17 = 29 or 90 + 01 = 100. Use the Pumping Lemma to prove that L is not regular