So to factorise binomials, you need to find the thing that both terms have in common. In this case, it is an 8 because 40 ÷ 8 = 5 and 16 ÷ 8 = 2. That means that an 8 goes outside the bracket, like 8(__). Now, we just find what we need to multiply 8 by to create 40t and -16, which is 5t and -2, so your answer is 8(5t - 2). I hope this helps!
