This is for my exit ticket can someone please help me understand

X = 7

Plz double check my work, in case it wrong. Dont want it to be wrong and then you be wrong

Step-by-step explanation:

If you need the answer 21, and you have to find a way to get what the value of X is, you will have to use subtraction from 21.

21 minus 10 = 11.

11 minus 4 = 7 There fore, the answer should be 7 for X

Double check it by doing (7 + 4) + 10 = 21

                                            11 + 10 = 21

                                               21 = 21