Using Further Mathematics in Normal A-level (Edexcel)?

For partial fractions, I am aware of both methods to solve (equating coefficients and the other substituting values in). I really prefer just equating the coefficients and then if I get a quadratic then just substituting into a 3 by 3 matrix and solving simultanously like this. This method is signicantly quicker and minmises mistakes for me but is it acceptable in an exam?

For partial fractions, I am aware of both methods to solve (equating coefficients and the other substituting values in). I really prefer just equating the coefficients and then if I get a quadratic then just substituting into a 3 by 3 matrix and solving simultanously like this. This method is signicantly quicker and minmises mistakes for me but is it acceptable in an exam?

my teacher told us not to mainly because sometimes mark schemes ask for a specific method and you could just end up only getting one mark for the answer- so better to be safe than sorry!