Answer : The equation could you use to find p is, 
Step-by-step explanation :
Let the cost of 1 pen be, 'x'
and the cost of 1 pencil is, 'p'
As we are given that total cost of 1 pen and 1 pencil is $2.10. The equation will be:
............(1)
And we have also given that the pen costs twice as much as a pencil. The equation will be:
............(2)
Now put the equation 2 in equation 1, we get:


Thus, the equation could you use to find p is, 
Full question attached
Answer:
Greenland offers the lowest unit rate, dollars per pound
Step-by-step explanation:
For McCoy, $4.5 = 5 pounds
Therefore $1 = 5pounds/4.5= 1.11 pounds
1 pound= 1/1.11= $0.9009
For Eat smart
$3=2 pounds
Therefore $1=2pounds/3 = 0.667 pounds
1 pound = 1/0.667= $1.499
For Greenland
$1/5= 1/4 pounds
$0.2=0.25 pounds
$1= 1.25 pounds
Therefore 1 pound= 1/1.25= $0.8
For Mother Nature
$0.95= 1 pound
Therefore Greenland offers the lowest unit rate at $0.8 per pound
Answer:
Angle 6, Angle 8, Angle 2, and Angle 4 are supplementary to Angle 7.
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