Algebra: Simplifying Surds
Without converting surds to decimals, simplify
( –1 – 2 √6)
3
=
+
√6
Worked Solution:
Either use the
Binomial Theorem
or multiply out 3 copies of the bracketed term:
( –1 – 2 √6)
3
= ( –2 √6)
3
+ 3 (–1) ( –2 √6)
2
+ 3 (–1)
2
(–2)√6 + (–1)
3
=
–8 √6
3
– 12
√6
2
– 6
√6
– 1
= –73 – 54 √6
©
MEI Produced by Dr Ron Knott, 21 July 2004
Test reference:
AlgSurdSimp.html?ref=31486,qu=pow