Answer:
The probability that a randomly chosen light bulb will last less than 900 hours is 0.1587.
Step-by-step explanation:
The life span of these light bulbs is normally distributed with a mean of 1000 hours and a standard deviation of 100 hours
Mean = 
Standard deviation =
We are supposed to find the probability that a randomly chosen light bulb will last less than 900 hours.i.e. P(x<900)
So, 

Z=-1
P(x<900)=P(z<-1)=0.1587
Hence the probability that a randomly chosen light bulb will last less than 900 hours is 0.1587.
Given
centre of circle O(3,2)=O(x0,y0)
point on circle P(6,-2)
Standard equation of circle:
(x-x0)^2+(y-y0)^2=r^2
r=radius of circle
= (distance OP)
= sqrt((6-3)^2+(-2-2)^2)
=sqrt(3^2+(-4)^2)
=sqrt(25)
=>
r^2=(sqrt(25))^2=25
Equation of circle
(x-x0)^2+(y-y0)^2=r^2
(x-3)^2+(y-2)^2=25 ............... standard equation of circle
Answer:
3y^2 - (y + 2) (y - 2) = 0
<=> 3y^2 - (y^2 - 4) = 0
<=> 2y^2 + 4 =0
<=>y^2 + 2 = 0
=> Because y^2 is always equal or larger than 0, there is no real solution.
Hope this helps!
:)
Three hundred and nine hundred thousand, and seventeen