ratios, proportions, and geometric means x/3=4x/x+3

Question

how do you solve this?

Answer 1

x/3 = 4x/(x + 3)

cross multiply:

x(x + 3) = 12x

distribute:

x^2 + 3x = 12x

subtract 12x from both sides:

x^2 - 9x = 0

factor:

x(x - 9) = 0

x = 0, 9

Answer 2

 

Pos: 2 . 0
Neg: 1 . 1
Img: 0 . 2
We know that there is a negative root for sure...
Possible roots:
a = 1,2,4,5,10,20
b = 1

Answer 3

Al's Awesome Autos advertised a special sale on cars - Dealer cost plus 5%!!
Jack and Margaret bought a luxury sedan for $23,727.90. What was the dealer's cost?

Answer 4

find the value of x in the proportion 20:50::8:x?

Answer 5

Shut