Answer: 45
Explanation:
I don't know if you mean the "x" as multiplication or as a variable, but I will assume it means multiplication.
First:
Calculate what is inside the brackets ( [ ] )
4x(3+5)+8
=4x8+8
=32+8
=40
Next:
15-5x2+40
=15-10+40
=5+40
=45