The error is in the fourth line where 24 minus negative 30 is incorrectly computed as 54. The correct result should be 24 + 30, which is 54.
The error is in the second step where (-12) is multiplied by (-30) instead of subtracted. The correct result is 54.
The error in the work is the subtraction of a negative number, which should be treated as addition. The correct result is 24 + 30 = 54.
