Everything Maths Grade 11

CHAPTER 3. SURDS 3.2

5 x− 16

√

y− 10

×

√

y + 10

√

y + 10

Step 2 : Multiply out the numerators and denominators

5 x

√

y− 16

√

y + 50x− 160

y− 100

All the terms in the numerator are different and cannot be simplified andthe

denominator does not have any surds in it anymore.

Example 6: Rationalise the denominator

QUESTION

Simplify the following:√y−y+5^25

SOLUTION

Step 1 : Rationalise the denominator

y− 25

√

y + 5

×

√

y− 5

√

y− 5

Step 2 : Multiply out the numerators and denominators

y

√

y− 25

√

y− 5 y + 125

y− 25

=

√

y(y− 25)− 5(y− 25)

(y− 25)

=

(y− 25)(

√

y− 25)

(y− 25)

=

√

y− 25

See video: VMeea at http://www.everythingmaths.co.za

Chapter 3 End of Chapter Exercises