Question

Solve the following simultaneous equations using Cramer’s rule :

3x - 2y = 3

2x + y = 16

Answer 1

3x - 2y = 3 .....(i)

2x + y = 16 ....(ii)

`D = |(3,-2),(2,1)| = 3(1) - 2(-2) = 7`

`D_x = |(3,-2),(16,1)|` = 3(1) - 16(-2) = 3 + 32 = 35

`D_y = |(3,3),(2,16)|` = 3(16) - 3(2) = 48 - 6 = 42

Now,

`x = D_x/D`     `y = D_y/D`

`x = 35/7`           `y = 42/7`

x = 5          y = 6