Question

x-y+2=0. 7x+9y-130=0 by cross multiplication method​

Answer 1

Answer:

Solution

Given equations are x−y+2=0 and 7x+9y=130

Comparing with a

1

x+b

1

y+c

1

=0 and a

2

x+b

2

y+c

2

=0 we have

a

1

=1,b

1

=−1,c

1

=2 and a

2

=7,b

2

=9,c

2

=−130

Now , x=

a

1

b

2

−a

2

b

1

b

1

c

2

−b

2

c

1

and y=

a

1

b

2

−a

2

b

1

c

1

a

2

−c

2

a

1

⇒x=

1×9−7×(−1)

−1×(−130)−9×2

and y=

1×9−7×(−1)

2×7−(−130)×1

⇒x=

9+7

130−18

and y=

9+7

14+130

⇒x=

16

112

and y=

16

144

⇒x=7 and y=9