Question

operation on like surds 18 root 7+18 root 7.​

Answer 1

Step-by-step explanation:

Multiplication of Surds

√5 × √15 = √75 (= 15× 5)

= √25 × √3

= 5 √3

(1 + √3)(2 - √8) [The brackets are expanded as usual]

= 2 - √8 + 2√3 - √24

= 2 - 2√2 + 2√3 - 2√6

Addition and Subtraction of Surds

Adding and subtracting surds are simple- however we need the numbers being square rooted (or cube rooted etc) to be the same.

4√7 - 2√7 = 2√7.

5√2 + 8√2 = 13√2

Note: 5√2 + 3√3 cannot be manipulated because the surds are different (one is √2 and one is √3).