Justin Ng's answer to Rhea mithrra's Secondary 1 Maths Malaysia question.

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Justin Ng
Justin Ng's answer
26 answers (Tutor Details)
1st
Observe that 9= 3^2 so 9^(z-1) = 3^2(z-1)

after that since both sides are in powers of 3, just compare the powers of 3 and into an algebriac equation of z= 2(z-1)