Question

Solve the following simultaneous equations by Cramer's method. 

`x+y=7,2x-3y=9` 

 

Answer 1

x + y = 7
2x - 3y = 9 

∴ `a_1=1, b_1=, c_1=7 and a_2=2, b_2=-3, c_2=9` 

Now, D= `|[a_1,b_1],[a_2,b_2]|`=` |[1 ,1],[2,-3]|` =`-3-2=-5` 

Dx=`|[c_1,b_1],[c_2 ,b_2]|=|[7,1],[9,-3]|=-21-9=-30` 

Dy=`|[a_1,c_1],[a_2,c_2]|=|[1,2],[2,9]|=9-14=-5` 

∴` x=(Dx)/D=-30/-5=6 and y=(Dy)/D=-5/-5=1`