Answer:
6.39*10^-4
Step-by-step explanation:
according to the form that is used to convert usual into scientific notation it be like 6.39*10^-4
Answer:
B y = -1/2x + 7/2
Step-by-step explanation:
We know that it has a negative slope since the points go from the top left to the bottom right
We can eliminate A and D
The y intercept is where it crosses the y axis
It should cross somewhere between 2 and 4
C has a y intercept of 9 which is too big
Lets verify with a point
x = -4
y = -4(-4)+9 = 16+9 = 25 (-4,25) not even close to being near the points on the graph
checking B
y = -1/2 (-4) +7/2
= 2 + 7/2 = 11/2 = 5.5 it seems reasonable
Answers A. and B. Are correct
Answer:

Step-by-step explanation:
Let x = the number of all the species of birds sighted in the park
“300 species of birds that migrate. This accounts for 2/7 of all the species of birds sighted in the park”
the above sentence means “(2/7)x = 300”
now we can solve it :
(2/7)x = 300
⇔ 2x = 7×300
⇔ 2x = 2100
⇔ x = 2100/2
⇔ x = 1050