Hello everyone.
I was watching the the “Matrix Inverse” video and I do not understand how the equations (shown in screenshot) are being solved. I tried elimination method but my results are different from the ones in the video.
Kindly someone explain what am I doing wrong.
Thank You
Screenshot:
Hello @annoyingCode I assume you’re asking how to find the values of the constants a,b,c,d
?
I haven’t checked the video on the methods that was used but here is a basic one:
 Let take 2 equations with common constants.
 Firstly, multiply both the given equations by some suitable nonzero constants to make the coefficients of any one of the variables (either a or c) numerically equal.
 After that, add or subtract one equation from the other in such a way that one variable gets eliminated.
(6a  1a = 5a), (2c  2c = 0), = (2  0 = 2) Hence
 Substitute this value in any of the given equations to get the value of another variable

1(2/5) + 2c = 0

2c = (2/5)

c = (1/5)
Repeat the same process to find b
and d
Let me know if this is what you were asking?
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Thank You so much for the reply.
Yes, I am asking the exact thing that you mentioned. Turns out, I was also doing the same except that I was taking the LCM wrong (a subtle mistake) but I am glad that I was able to find the error.
Thank You for the help. I really appreciate it.
Welcome @annoyingCode . Happy to hear you have figured it out
Happy learning
Isaak Kamau