Answer:
Girls in Mr. Chang's class: 28 - 21 ; # girl students = # total students - # boy students ; 7 girl students.
Boys in Mr. Chang's class: 28 - 7 ; # boy students = # total students - girl students ; 21 boy students.
Answer:
The third one, x+(x+1)+(x+2)=-21 because x, x+1 and x+2 are three consecutive numbers.
It would be (x−9)(x+4)<span>
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