A and B are two linear equation in two variable x and y. (0,1) is a solution of both A and B, (2,-1)

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05 May 2016 Linear Equations

A and B are two linear equation in two variable x and y. (0,1) is a solution of both A and B, (2,-1) is a solution of A only and (-2,-1) is a solution of B only. A and B are.

OPtion

1) x=0, y=1
2) x=0, x-y=-1
3) x+2y=2, 4x+y=1
4) 2x-y=-1, x-y=-1
5) x+y=1, x-y=-1
6) x+2y=2, x-y=-1
7) 2x-y=-1, 4x+y=1
8) x+y=1, x-y=-2
9) 2x-y=1, x-y=-1
10)x+2y=2, x+y=1

Solution

Let A and B be the equations given by ax+by=c and lx+my=n
Since (0,1) satisfies these equations, we have b=c and m=n
Since (2-1) satisfies ax+by=c, we have 2a-b=c
Therefore
2a-b=b or a=b (c=b)
Again
(-2,-1) satisfies lx+my=n we have -2l-m=d
or -2l-m=m or l=-m
Thus a=b=c and l=-m=-n
So the equation are
x+y=1 and x-y=-1
option 5)

Correct Option: 5 Best Solution (4)

Aakash Beniwal   8 years AGO

Put values (2,-1) in 5th each eq. 1st eq. and (-2,-1) in second.

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sowmya   8 years AGO

checking the options with given solutions.
A(2,-1) can be solved by X+Y=1
B(-2,-1) can be solved by X-Y=-1
and given both should get solution set as(0,1) if we solve the above two equations we will get solution as given

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Tejaswi   8 years AGO

y=mx+c Y=MX+C
Substituting (0,1)
We get C=c=1
By substituting (2,-1) &(-2,-1)
We get x+y=1
X-Y=-1

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Vipul kumar   8 years AGO

Because it is the only set of equation that satisfying all conditions...

(0,1) satisfying both equation

x+y=1 => 0+1=1 => 1=1

x-y=-1 => 0+(-1)=-1 => -1=-1



(2,-1) satisfying first equation

x+y=1 => 2+(-1)=1 => 1=1

(-2,-1) satisfying second equation

x-y=-1 => (-2)-(-1)=-1 => -2+1=-1
=> -1=-1

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