Answer:
8a(5a - 4)
Step-by-step explanation:
To factor this expression, see what numbers and variables these two terms have in common. I can see that they both have the variable a, so a can be factored out.
40 and -32 also have 8 in common, because they are both cleanly divisible by 8.
Now we can factor 8a out of 40a^2 - 32a. Think of how many times 8a goes into 40a^2 and -32a.
8a(5a - 4)