LIM JI HWEE's answer to Mq's Secondary 3 A Maths Singapore question.

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LIM JI HWEE
Lim Ji Hwee's answer
29 answers (Tutor Details)
Again, key is to identify value(s) of X that will allow you to completely eliminate one unknown to solve for the other one, in this case, solve for B by letting x be 1/3 (as this will cause A to disappear in the equation).