Domain is (-infinity, infinity)
Range is [8, infinity)
34 books would be the answer.
12,000
8,000
1400
7
hope this helps
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
