You multiply the exponents together to get a single exponent, in this case, 15
        
                    
             
        
        
        
The "k" value should have units and should be negative.
k = -.07 / seconds
Half-Life = ln (.5) / k
Half-Life = ln (.5) / -.07
Half-Life = -.693147 / -.07
Half-Life = 9.9 seconds
(actually, wkpedia says half-life of Krypton 91 is 8.57 seconds)
elapsed time = half-life * log (bgng amt / end amt) / log (2)
elapsed time = 9.9 * log (100 / 10) / 0.30102999566
elapsed time = 9.9 * 1 / 0.30102999566
<span><span>elapsed time = 9.9 * 3.3219280949
</span>
</span><span><span><span>elapsed time = 32.8870881395
</span>
</span>
</span>
<span>elapsed time = 32.89 seconds (rounded)
Source:
http://www.1728.org/halflife.htm
</span>
        
                    
             
        
        
        
The formula for finding the area of a rug: 

Plugging in the values we know, we can solve for s.

Take the square root of both sides.


 is approximately equal to 8.89
So, 8.89 feet is the answer.
 
        
        
        
Answer:
A
Step-by-step explanation:
to solve absolute value inequalities you must solve it for when the absolute value is positive and then when it is negative
example, |4| = 4 and -4
first solution will be when we're solving for the positive value:
+(-4x+7) ≥ 27
-4x + 7 ≥ 27
-4x ≥ 20
x ≤ -5   [reverse the symbol when mult or div by a negative]
-(-4x+7) ≥ 27
4x - 7 ≥ 27
4x ≥ 34
x ≥ 34/4 or x ≥ 8 1/2
solution:  x ≤ -5 or x ≥ 8.5
 
        
             
        
        
        
Solute = what is dissolved
solvent = that which dissolves or can dissolve
You take it from here.