Answer:

Step-by-step explanation:
In order to add or subtract numbers in scientific notation, the powers of ten must have the same exponent. In this caes the diameter of an average human body cell is a power of -4 and the diameter of a plant cell is a power of -3. In order to add them, we can move the decimal over for the body cell diameter:

Add the two values: 
Answer:
12 less than or equal to 2
Step-by-step explanation:
Answer:
y = x/3 + 7
Step-by-step explanation:
Use the equation: y - y1 = m(x - x1)
Plug in the given values into the equation:
y - 5 = (1/3)(x + 6)
Simplify the right side:
y - 5 = (x/3) + 2
Finally, add 5 to both sides:
y = x/3 + 7
Answer:
C
Step-by-step explanation: