WAEC - Further Mathematics (2012 - No. 29)
Find the constant term in the binomial expansion of \((2x - \frac{3}{x})^{8}\).
90720
1296
1120
672
Explanation
\((x)^{n}(x^{-1})^{8 - n} = x^{0}\)
\(x^{n} . x^{-8 + n} = x^{0} \implies n - 8 + n = 0\)
\(2n - 8 = 0 \implies n = 4\)
Constant term = \(^{8}C_{4}(2^{4})(3^{4}) = 70 \times 16 \times 81\)
= \(90720\)
Comments (0)
