Question

Value of 1/√18-√32 is equal to:
a) √2
b) -√2
c) 1/√2
d) - 1/√2

Answer 1

Answer:

by rationalising

1/ √18 -√32 × √18+√32/√18+√32

= (√18+√32)/ (√18)²-(√32)²

= (√18+√32)/18-32

= (√18+√32)/-14

identity used-

(a-b)(a+b) = a²-b²

√18 = √2×3×3

= 3√2

√32 = √2×2×2×2×2

= 4√2

√18+√32

= 3√2+4√2

= 7√2

7√2/-14

= -√2/2

= -1/√2

option (d)

Answer 2

Answer:

-1/√2

Step-by-step explanation:

1/√18-√32

1/√2x3x3-√2x2x2x2x2

1/3√2-4√2

1/-√2

Hence, (d) -(1/√2) ------> Answer