Bobby claims that Peter started with 21 cards. Which statements are true about verifying Bobby’s claim? Check all that apply.
A
Substitute 21 for x in the original equation.B
Substitute any number for x in the original equation.C
Bobby’s claim that x = 21 is correct.D
The result of verifying Bobby’s work is 9 = 9.E
The result of verifying Bobby’s work is 21 = 21.