Question

Use? Cramer's rule to solve the system or to determine that the system is inconsistent or contains dependent equations.?

x+y=7

x-y=5

Find the determinants: D,Dx,Dy?

Answer 1

solution using Cramer's rule

Your matrix

	X1	X2	b
1	1	1	7
2	1	-1	5

Write down the main matrix and find its determinant

	X1	X2
1	1	1
2	1	-1

D = -2

Very detailed solution  

Replace the 1st column of the main matrix with the solution vector and find its determinant

	X1	X2
1	7	1
2	5	-1

Dx = -12

Very detailed solution  

Replace the 2nd column of the main matrix with the solution vector and find its determinant

	X1	X2
1	1	7
2	1	5

Dy = -2

Very detailed solution  

x = Dx / D = (-12) / (-2) = 6

y = Dy / D = (-2) / (-2) = 1

Solution set:

x = 6

y = 1