Divide -4 from both sides to isolate the t
Note: When you DIVIDE a negative number (as in the negative number is located in the denominator when dividing) you must flip the sign.
−4t ≤ 48
-4t(/-4) ≤ 48(/-4)
t ≤ 48/-4
t ≥ -12
t ≥ -12 is your answer
hope this helps