Answer: 41.5 min
Step-by-step explanation:
This problem can be solved with the Radioactive Half Life Formula:
(1)
Where:
is the final amount of the radioactive element
is the initial amount of the radioactive element
is the time elapsed
is the half life of the radioactive element
So, we need to substitute the given values and find
from (1):
(2)
(3)
(4)
Applying natural logarithm in both sides:
(5)
(6)
Clearing
:
This is the time elapsed
6x² - 5x + -21 = 0
Because this whole equation equals zero, we must simply factorize the first half of the equation, or the left side.
(3x - 7)(2x + 3) = 0
I was never really taught a specific way to factorize, so I usually just guess and check when factorizing. It usually takes a long time, it always gives you the tight answer.
Then, take each equation and make it equal zero.
3x - 7 = 0 AND 2x + 3 = 0
3x - 7 = 0
Add 7 to both sides.
3x = 7
Divide both sides by 3.
x = 7/3
Now, we do our second equation.
2x + 3 = 0
Subtract 3 from both sides.
2x = -3
Divide both sides by 2.
x = -3/2
So, x = 7/3 AND x = -3/2
So, your answer is C) x = 7/3, x = -3/2
~Hope I helped!~
If it’s division try 13 not rlly sure so don’t give me hate if it wrong
P = 2(L + W)
510 = 2(L + W) ...divide both sides by 2
510/2 = L + W
255 = L + W
3/5(255) = 765/5 = 153 cm <== length
2/5(255) = 510/5 = 102 cm <== width
THERE ARE 52 WEEKS IN A YEAR.
40 (hours) x 52 (weeks) = 2080
29460 / 2080 = 14.25
He made a. $14.25 per hour.