Because x,y,z form a geometric sequence, therefore the common ratio is
r = y/x = z/y
That is,
y² = xz (1)
We are given:
x + y + z = 18
Therefore
x + z = 18 - y (2)
Also,
x² + y² + z² = 612
Therefore, from (1), obtain
x² + z² + xz = 612
(x + z)² - xz = 612
From (1) and (2), obtain
(18 - y)² - y² = 612
324 - 36y + y² - y² = 612
-36y = 288
y = -8
Answer: y = -8
Answer:
x = -1.59
Step-by-step explanation:
We are here given a equation and we need to solve out for x. The given equation is ,
Take log to the base " e " on both sides , so that we can remove the variable from the exponent .
Simplify using the property of log , 
, we have ,
Distribute by opening the brackets ,
This can be written as ,
Divide both sides by ln 4 ,
Simplify ,
On simplifying , we will get ,
The probability of choosing. a green pen is 0.25
<h3>What is probability?</h3>
Probability is the likelihood or chance that an event will occur. Mathematically;
Probability = Expected/Total outcome
If a bag has 3 blue pens, 6 red pens, and 3 green pens, then;
Total pen = 3+6+3
Total pen = 12
If a green pen is chosen, then
Pr(choosing a green pen) = 3/12
Pr(choosing a green pen) = 0.25
Hence the probability of choosing. a green pen is 0.25
Learn more on probability here: brainly.com/question/25870256
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X is how much it costs for one hour, so when you multiply it by 3 1/2, you get the amount of money charged for 3 and a half hours.
