Question

Solve the following simultaneous equation using cross-multiplication method. x+2y-10=0 and 4x - y - 4 = 0​

Answer 1

Answer:

3x+2y=10---(1)

4x−2y=4---(2)

Using formula for cross multiplication method:

(b

1

c

2

−b

2

c

1

)

x

=

(c

1

a

2

−a

1

c

2

)

y

=

(a

1

b

2

−a

2

b

1

)

−1

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

2×4−(−2)×10

x

=

10×4−3×4

y

=

3×(−2)−4×2

−1

8+20

x

=

40−12

y

=

−6−8

−1

28

x

=

28

y

=

−14

−1

28

x

=

−14

−1

−14x=−28

x=2

28

y

=

−14

−1

−14y=−28

y=2

Therefore, x=2,y=2

Answer 2

Answer:

Correct option is

D

x=2,y=2

3x+2y=10---(1)

4x−2y=4---(2)

Using formula for cross multiplication method:

(b

1

c

2

−b

2

c

1

)

x

=

(c

1

a

2

−a

1

c

2

)

y

=

(a

1

b

2

−a

2

b

1

)

−1

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

2×4−(−2)×10

x

=

10×4−3×4

y

=

3×(−2)−4×2

−1

8+20

x

=

40−12

y

=

−6−8

−1

28

x

=

28

y

=

−14

−1

28

x

=

−14

−1

−14x=−28

x=2

28

y

=

−14

−1

−14y=−28

y=2

Therefore, x=2,y=