Given that y =(\(\frac{pr}{m} - p^2r\))\(^{\frac{-3}{2}}\) (a) make r the subject; (b) find the value...

MATHEMATICS
WAEC 2020

Given that y =(\(\frac{pr}{m} - p^2r\))\(^{\frac{-3}{2}}\)

(a) make r the subject;

(b) find the value of r when y = -8, m = 1 and p = 3.

Explanation

(a) y =(\(\frac{pr}{m} - p^2r\))\(^{\frac{-3}{2}}\)

y\(^{\frac{-2}{3}}\) =(\(\frac{pr}{m} - p^r2\))

my\(^{\frac{-2}{3}}\) =(\(\frac{pr- p^r2m}{m}\))

my\(^{\frac{-2}{3}}\) = pr - p\(^2\)rm

my\(^{\frac{-2}{3}}\) = r(p - p\(^2\)m)

r = (\(\frac{my^{-2/3}}{m - p^2m}\))

(b) r = (\(\frac{1-8^{-2/3}}{3 - 3^2 * 1}\))

= \(\frac{1}{4}\) ÷ -6

= - \(\frac{1}{-6}\)

= - \(\frac{1}{24}\)



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