# FAQ: Linear Algebra with Python - Review

This community-built FAQ covers the “Review” exercise from the lesson “Linear Algebra with Python”.

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""" Given this set of equations: 2a + 3d - 2c = 4 -c + 4b - a = 1 2d - 2c + 3a - b = 2 -2a + 3c - b = -2 """ #here's my corresponding matrix and vector A = np.array([[2,0,-2,3],[-1,4,-1,0],[3,-1,-2,2],[-2,1,3,0]]) b = np.array([4,1,2,-2]) #here's the solution: A = np.array([[2, -1, 3, -2],[0, 4, -1, -1],[-2, -1, -2, 3], [3, 0, 2, 0]]) b = np.array([4, 1, 2, -2])

In the solution the first vector in the matrix contains 4 elements [2, -1, 3, -2] but in the actual equation there’s only 3 elements? Am I missing something here, I tried to solve it like the last exercise.

Thanks

1 Like

Hi! I faced the same issue and googled. I think the solution answer is wrong as it collates the x values from across all the equations into the same row. Had to find out but this link should help. Your answer is correct

3 Likes

I agree that the solution is wrong. This is a good primer on how to solve systems of linear equations.