Can someone answer this question please answer it correctly please show work please help me if it’s correct I will mark you brainliest

What is the value of x when x + 7 = 21?

Bella want to know what the students at her school think of her show. which is the best group to survey to find this information a. go to the mall and ask all of the students she recognizes from school b. ask her viewers to call in durning an episode of the show c. get a list of students at her school from the office and use a random number generator to pick 30 of them d. get a list of students at her school from the office and pick the first 30 students on the list

Hey free points ! people i have a few math questions on my profile consider looking at them i have to get done in 30 mins!