X2=9 has only one solution, which is 4.5
You would need to know the cost of the box of 20, then you would divide the total cost by the number of pencils in the box. This would give you the cost of one pencil - which is the unit cost.
Example:
Lets say the box of 20 pencils cost $10.
Divide the total cost by the number of pencils:
10 / 20 = 0.50 - This means each pencil cost 50 cents, so the unit cost would be 50 cents per pencil.
Answer:
y = -x + 17
Step-by-step explanation:
A(-10,-3)
B(7,14)
C(5,12)
Need line CD perpendicular to AB through C.
Solution:
slope of AB, m1 = (yb-ya) / (xb-xa) = (14- -3) / (7- -10) = 17/17 = 1
Slope of CD, m2 = -1/m1 = -1 / 1 = -1
Line CD through C, using the point slope form
y-yc = m2(x-xc)
y-12 = -1 (x-5)
rearrange
y = -x + 5 + 12
y = -x + 17
Answer:
Table 1
Step-by-step explanation:
To determine if it is proportional, y/x must be constant
Table 1
y/x = .5/1 = 1/2
1/2 =
3.5/7 = 1/2
4/8 = 1/2
This is constant
Table 2
y/x = 1/3
2.5/ 7.5 = 1/3
4/15 = 2/5 so it is not constant
Table 3
y/x = 12/3 =4
15/6 =5/2 not constant
Table 4
y/x = 7/2
9/3 = 3 not constant
The amount of substance left of a radioactive element of half life,
after a time, t, is given by:
Given that <span>potassium-40 has a half life of approximately 1.25 billion
years.
The number of years it will take for 0.1% of potassium-40 to remain is obtained as follows:
Therefore, </span><span>the maximum age of a fossil that we could date using 40k is
12.5 billion years.</span>