21
12
-16
n + 13 = 21. n = 21 - 13
3, 7, 21. 3x7 is the only equation that equals 21, and so these are the only factors of 21.
32
9+12
It is an equation and the value of x is 7
120 - 90x = 210
21
5
If the equation is 7x - 3y = 21 then (3, 0) and (0, -7).