Answer:
Points P ( 4 , - 7 ) and Q ( 1 , 5 ) belong to the equations:
1 ; 4 ; and 5
Step-by-step explanation:
Equations 1 ; 4 and 5 are the same equation
Equation 1 y = - 4*x + 9
Equation 4
y + 7 = - 4 * ( x - 4 ) ⇒ y + 7 = - 4*x + 16 ⇒ y = - 4*x - 7 + 16
y = -4*x + 9
Equation 5
4*x + y = 9 ⇒ y = - 4*x + 9
Now for the equation y = - 4*x + 9
P ( 4 , -7)
For x = 4 y = - 4*(4) + 9 ⇒ y = - 16 + 9 ⇒ y = - 7
Then point P is in the line y = - 4*x + 9
Point Q (1 , 5 )
For x = 1 y = - 4 * ( 1) + 9 ⇒ y = - 4 + 9 ⇒ y = 5
Point Q is in the line y = - 4*x + 9
Equation 2
y = - 4*x - 23
Point P ( 4 , - 7 )
For x = 4 y = 16 - 23 y = - 7
Point P is in the line
Point Q
For x = 1 y = - 4 *(1) - 23 ⇒ y = - 27
Then poin Q is not in the line
Equation 3
y - 1 = - 4 * ( x - 4 )
y - 1 = -4*x + 16 ⇒ y = - 4*x + 17
Point P ( 4 , - 7 )
For x = 4
y = - 16 + 17 ⇒ y = 1
Point P is not in the line
And Point Q ( 1 , 5 )
For x = 1
y = - 4* ( 1 ) + 17 ⇒ y = 13 Q is not in the line
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>
You are right ! It is 8.246 and so on ;)
Answer: b/65=7/13
65/13=5
35/7=5
Step-by-step explanation:
