Question

solve by closs multiplication method: 9 - (x - 4) = y + 7 , 2(x + y) = 4 -3y

Answer 1

Answer:

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)