Answer:
7
Step-by-step explanation:
Using fundamental theorem of algebra, there should be 7 roots, if you count multiplicity.
If you're only counting distinct roots, then there should be 4 roots.
10 to the 5th power means 5 times zero, place 8 before that and it will be 800000 then multiply with 0.5 it will be 400000. In scientific notation it will be like 4x10 the 5th power.
Usually you use addition to find a sum.
Try to do them on math -way