Let the three gp be a, ar and ar^2
a + ar + ar^2 = 21 => a(1 + r + r^2) = 21 . . . (1)
a^2 + a^2r^2 + a^2r^4 = 189 => a^2(1 + r^2 + r^4) = 189 . . . (2)
squaring (1) gives
a^2(1 + r + r^2)^2 = 441 . . . (3)
(3) ÷ (2) => (1 + r + r^2)^2 / (1 + r^2 + r^4) = 441/189 = 7/3
3(1 + r + r^2)^2 = 7(1 + r^2 + r^4)
3(r^4 + 2r^3 + 3r^2 + 2r + 1) = 7(1 + r^2 + r^4)
3r^4 + 6r^3 + 9r^2 + 6r + 3 = 7 + 7r^2 + 7r^4
4r^4 - 6r^3 - 2r^2 - 6r + 4 = 0
r = 1/2 or r = 2
From (1), a = 21/(1 + r + r^2)
When r = 2:
a = 21/(1 + 2 + 4) = 21/7 = 3
Therefore, the numbers are 3, 6 and 12.
Answer:
$3.50
Step-by-step explanation:
15 min is 1/4 hr.
Working an add'l 1/4 hr brings the employee additional pay:
($14/hr)(1/4 hr) = $7/2, or $3.50
Answer: Peyton
Step-by-step explanation:
Michelle: Greatest common factor is 1
Naomi: Greatest common factor is abc
Olivia: Greatest common factor is 2ab
Peyton: Greatest common factor is ab
Answer:
625 cm³ and 64000 cm³
Step-by-step explanation:
Given
x = ![\sqrt[3]{V}](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7BV%7D)
( cube both sides )
x³ = V
(a)
x = 25 cm , then
V = 25³ = 625 cm³
(b)
x = 40 cm , then
V = 40³ = 64 000 cm³
