rewrite the equations as matrices, -19x=-4y+12, and 4y=-3x+100

Question

Use Cramer's Rule to solve the matrices. Show all your calculation.

Answer 1

rearrange the equations to become: -19x + 4y = 12 3x + 4y = 100 augmented matrix is: -19 4 : 12 3 4 : 100 Determinant A = -19*4 - 3*4 = -88 Determinant Ax (replace the x column with the constants) resulting matrix: 12 4 100 4 so Determinant Ax = 12*4 - 100*4 = -352 x = Determinant Ax / Determinant A x = -352 / -88 x = 4 Determinant Ay (replace y column with the constants) resulting matrix: -19 12 3 100 Determinant Ay = -19*100 - 3*12 = -1936 y = Determinant Ay/Determinant A = -1936/-88 y = 22 checking: -19 ( 4 ) = -4 (22) + 12 - 76 = -76 correct 4 (22) = -3 (4) + 100 88 = 88 correct