Algebra: Simplifying Surds
Without evaluating square roots as decimals, simplify
3 + √5
2 – √5
=
+
√5
Worked Solution:
Rationalise the denominator
by multipling both numerator and denominator by
2 + √5
:
3 + √5
2 – √5
=
(3 + √5)(2 + √5)
(2 – √5)(2 + √5)
=
6 + 3 √5 + 2 √5 + √5
2
4 – √5
2
=
11 + 5 √5
–1
=
–11
–5
√5
©
MEI Produced by Dr Ron Knott, 21 July 2004
Test reference:
AlgSurdSimp.html?ref=83352