Question

solve: x-y= -1 and 2x-3y=7 by the elimination method
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Answer 1

${\red{\underline{\underline{\bold{Given:-}}}}}$

• x - y = -1 ----------(1)
• 2x - 3y = 7 ----------(2)

${\blue{\underline{\underline{\bold{To\:Findn:-}}}}}$

• Value of x & y by, elimination method .

${\green{\underline{\underline{\bold{Solution:-}}}}}$

• x - y = -1 ---------(1)
• 2x - 3y = 7 ----------(2)

Elimination Method:-

Multiply the equation (1) with 2

2(x-y = -1)

2x - 3y = 7

We get,

2x -2y = -2--------(3)

2x - 3y = 7--------(4)

Subtract equation (1) and (2). Eliminate x

We get,

==> 3y - 2y = -7-2

==> y = -9

Keep Value of y in equ(1)

==> x - (-9) = -1

==> x + 9 = -1

==> x = -1-9

==> x = -10

Hence,

Value of x = -10

Value of y = -9

________________

${\pink{\underline{\underline{\bold{Answer\: Verification:-}}}}}$

Case(1).

Keep value of x & y in equ(1)

==> -10-(-9) = -1

==> -10+9 = -1

==> -1 = -1

L.H.S. = R.H.S.

______________________

Case(2).

Keep value of x & y in equ(2)

==> 2(-10) -3(-9) = 7

==> -20 + 27 = 7

==> 7 = 7

L.H.S. = R.H.S.

$\mathbf\orange{Hence\:Proved}$

Answer 2

x-y=-1.......(1)

2x-3y=7......(2)

Multiplying.......(1) by 2

2x-2y=-2........(3)

Subtract .....(3) from...(2)

2x-3y=7

-

2x-2y=-2

-y=9

y=-9

Substitute the value of y in .....(1)

x-(-9)=-1

x+9=-1

x=-1-9=-10

X=-10 and Y=-9