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# Given that y is inversely proportional to (x-1). (a)write down an expression for y in terms of x and a constant k. (b)it is given that y=5 when x=3. find x when y=25.

i am doing my school homework
Question asked by: zOhyEE

Asked on: 30 Dec 2008

A). y is inversely proportional to x-1 means y=k/x-1, where k represents the proportionality constant.
y=5 when x=3, substituting these values into the expression: 5=k/3-1; 5=k/2. Transpose the expression for x by multiplying both sides by 2. Hence, k=2*5=10.
b). to find x when y=25, put y =25 and k=10 into the expression
y=k/x-1; 25=10/x-1. Multiply both sides by x-1: 25(x-1)=10. Divide both sides by 25: x-1=0.4. Add 1 to both sides: x=1.4
Hence, x=1.4 when y=25.

By: goodboy
Replied at: 03 Jan 2009
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