Question

3x-4y=-7 & 5x2y=0 by cramers rule

Answer 1

Step-by-step explanation:

D=[3 -4]

[5 2]

= 3×2-5×-4

= 6+20=26

Dx= [-7 -4]

[0 2]

= -7×2-0×-4

= -14+4

= 18

Dy = [ 3 -7]

[ 5 2]

= 3×2-5×-7

= 6 +35

= 41

Answer 2

Answer:

The solution of the given simultaneous equations is ( x, y ) = ( 1, 5 / 2 ).

Step-by-step-explanation:

The given simultaneous equations are

3x - 4y = - 7 - - - ( 1 )

5x - 2y = 0 - - - ( 2 )

Now, comparing equation ( 1 ) with a₁x + b₁y = c₁, we get,

3x - 4y = - 7 - - - ( 1 )

• a₁ = 3
• b₁ = - 4
• c₁ = - 7

Now, comparing equation ( 2 ) with a₂x + b₂y = c₂, we get,

5x - 2y = 0 - - - ( 2 )

• a₂ = 5
• b₂ = - 2
• c₂ = 0

Now, we know that,

Refer to attachment 1.

⇒ D = 3 * ( - 2 ) - [ ( - 4 ) * 5 ]

⇒ D = - 6 - ( - 20 )

⇒ D = - 6 + 20

⇒ D = 14

Now, we know that,

Refer to attachment 2.

⇒ Dₓ = ( - 7 ) * ( - 2 ) - [ ( - 4 ) * 0 ]

⇒ Dₓ = 14 - 0

⇒ Dₓ = 14

Now, we know that,

Refer to attachment 3.

⇒ Dᵧ = 3 * 0 - [ ( - 7 ) * 5 ]

⇒ Dᵧ = 0 - ( - 35 )

⇒ Dᵧ = 0 + 35

⇒ Dᵧ = 35

Now, by Cramer's rule,

x = Dₓ / D

⇒ x = 14 / 14

⇒ x = 1

Now, by Cramer's rule,

y = Dᵧ / D

⇒ y = 35 / 14

⇒ y = 5 / 2

∴ The solution of the given simultaneous equations is ( x, y ) = ( 1, 5 / 2 ).