An electric cable cost Rs 200 .if the cable was 5 metres longer and each metre Of cable cost Rs 2 less, the cost of cable would have remained unchanged. Represent the above situation in the form of ax^2+bx+c=0.
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Let the cost of each metre be y and the length of the cable in metres be x.
XY=200
X=200/y
The new length is x+5 and the cost be y-2.
(x+5)(y-2)=200
Substituting x for 200/y we get
(200/y + 5)(y-2)=200
((200+5y)/y)(y-2)=200
(200y-400+5y^2-10y)/y=200
200y-400+5y^2-10y=200y
5y^2+190y-400=200y
5y^2-10y-400=0
Since your question is only asking for representation, I am leaving the answer here. You can break the middle term as +40y-50y.
XY=200
X=200/y
The new length is x+5 and the cost be y-2.
(x+5)(y-2)=200
Substituting x for 200/y we get
(200/y + 5)(y-2)=200
((200+5y)/y)(y-2)=200
(200y-400+5y^2-10y)/y=200
200y-400+5y^2-10y=200y
5y^2+190y-400=200y
5y^2-10y-400=0
Since your question is only asking for representation, I am leaving the answer here. You can break the middle term as +40y-50y.
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