Find the missing value to make the point (_, 21) on the equation y = 3x - -9

Answer 1

To find the missing value to make the point (_, 21) on the equation y = 3x - -9, we can substitute y = 21 into the equation and solve for x.

21 = 3x - -9
21 = 3x + 9
12 = 3x
x = 4

Therefore, the missing value to make the point (4, 21) on the equation y = 3x - -9.