SOLUTION: When a stone is dropped into a deep well, the number of seconds t until the sound of a splash is heard is given by the formula T=√x/4+x/1100 where x is the depth of the wel

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Question 628433: When a stone is dropped into a deep well, the number of seconds t until the sound of a splash is heard is given by the formula
T=√x/4+x/1100
where x is the depth of the well in feet. If it takes 9 seconds to hear a splash, how deep (to the
nearest foot) is the well?

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
When a stone is dropped into a deep well, the number of seconds t until the sound of a splash is heard is given by the formula
T=√x/4+x/1100
where x is the depth of the well in feet. If it takes 9 seconds to hear a splash, how deep (to the
nearest foot) is the well?
T=√x/4+x/1100
9=√x/4+x/1100
LCD:4*1100
1100√x+4x=9*4*1100=39600
1100√x+4x-39600=0
275√x+x-9900=0
let u=√x
u^2=x
..
u^2+275u-9900=0
Solve by following quadratic formula:
+u=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a=1, b=275, c=9900
ans:
u=32.2=√x
square both sides
x≈1037 ft