JAMB - Mathematics (1993 - No. 7)
If 2log3 y + log3 x2 = 4, then y is
4 - log3
\(\frac{4}{log_3 x}\)
\(\frac{4}{x}\)
\(\pm\) \(\frac{9}{x}\)
Spiegazione
2log3y + log3x2 = 4
log3y2 + log3x2 = 4
∴ log3 (x2y2) = log381(correct all to base 4)
x2y2 = 81
∴ xy = \(\pm\)9
∴ y = \(\pm\)\(\frac{9}{x}\)
log3y2 + log3x2 = 4
∴ log3 (x2y2) = log381(correct all to base 4)
x2y2 = 81
∴ xy = \(\pm\)9
∴ y = \(\pm\)\(\frac{9}{x}\)