Answer:
The number is 1
Explanation:
Let the number be x
Subtract 8 from x ==> x - 8
Multiply by -3 ==> -3(x - 8) = -3(x) -3(-8) = -3x - 24
This equals 21
So
-3x + 24 = 21
Subtract 24 from both sides:
-3x + 24 - 24 = 21 - 24
==> -3x + 0 = - 3
-3x = -3
Divide by -3
==> -3x/-3 = -3/-3
x = 1
Check
1 - 8 = -7
-3(1-8) = -3 x -7 = 21