Answer: 6.93 years
Step-by-step explanation:
Given
Rate of interest is 
Future value is given by 
For the investment to double itself, i.e. 

It takes around 6.93 years to double the investment.
4(x -2) +(y +5) = 0 . . . . . an equation
4x +y = 3 . . . . . . . . . . . . the equation in standard form
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A graph can be seen at
https://www.desmos.com/calculator/3ct9gfxclj
Step-by-step explanation:
Chord AB and Chord CD are equidistant from the center of the circle.

56,000 in standard notation