Thread: Solving linear equation using matrices Can some please check?!?

Hi could some one please check this work, it's to solve the following system of linear equations using matrices.
-3x-2y=15
-9x+8y=3

As a matrice
[-3 -2] [x] [15]
[-9 8] [y] [3]

Determinant (-3)*8-(-2)*(-9)=-42

[-8/-42 -2/-42]
[-9/-42 -3/42]

[-4/-21 -2/21]
[-3/14 1/14]

-4/21*15 + -1/21*3=-3
-3/14*15 +1/14*3 =-3

x=-3 y=-3

Many thanks

You can check the answer to any "solving" problem by plugging it back in to the original exercise. In your case, plug in your values for "x" and "y", and see if they work:

. . . . .-3[-3] - 2[-3] = 9 + 6 = 15 (yes!)

. . . . .-9[-3] + 8[-3] = 27 - 24 = 3 (yes!)

Since your solution values "check", your answer must be correct.

Good work!

P.S. Thank you for showing all your work!!

Praise!!
many thanks.

S