Question

4x+6y=9 and 2x-3y=-11 find the value of x and y using cross multiplication method?

Answer 1

Answer:

9x+6y=12 ----- (1)

4x+6y=14 ----- (2)

First use formula for cross multiplication method:

b

1

c

2

−b

2

c

1

x

=

c

1

a

2

−a

1

c

2

y

=

a

2

b

2

−a

2

b

1

−1

So, from equation (1) and (2) we can write the value of a, b and c.

(−6)×14−6×12

x

=

12×4−9×14

y

=

9×6−4×(−6)

−1

−84−72

x

=

48−126

y

=

54+24

−1

−156

x

=

−78

y

=

78

−1

−156

x

=

78

−1

x=

78

156

=2

−78

y

=

78

−1

y=

78

78

y=1

The solution is (2, 1)