Question

simplify 2xy (9×2-y2)​

Answer 1

Let

x+y

1

=X and

x−y

1

=Y

3X+2Y=2 ...(i)

9X−4Y=1 ...(ii)

On multiplying (i) by 3 and (ii) by 1 and subtracting, we get

9X+6Y=6

−

9

X

+

−

4Y=

−

1

10Y=5

∴Y=

2

1

On putting Y=

2

1

in (i), we get

3X+2×

2

1

=2⇒X=

3

1

∴

x+y

1

=

3

1

and

x−y

1

=

2

1

⇒x+y=3 ...(iii)

x−y=2 ...(iv)

On adding (iii) and (iv), we get

2x=5⇒x=

2

5

On putting x=

2

5

in (iii), we get

2

5

+y=3⇒y=3−

2

5

=

2

1

∴x=

2

5

,y=

2

1