Answer:
b = -10
Step-by-step explanation:
2(b + 3) = b – 4
2b + 6 = b - 4
-b -b
b + 6 = -4
-6 -6
b = -10
2,6,18,54 because they have a common ratio of 3
The distance in kilometers in scientific notation 
<h3>Scale factors</h3>
Scale factors are values or constants multiplied with a variable
If Alvin and Simon raced a distance of
kilometers and they need to race 7 times that distance in a kilometer, the distance traveled will be:
- Distance travelled =

- Distance travelled =

Hence the distance in kilometers in scientific notation 
Learn more on distance here: brainly.com/question/23848540
Answer:
10x-40
Step-by-step explanation:
5 times 2x minus 40 works because of the distributive property