Question

2.
Find the cube of the following numbers by adding consecutive odd numbers:
(a) 11
(b) 14
(c) 22
(d) 39​

Answer 1

Answer:

(a) 11 - 1331

(b) 14- 2744

(c) 22-10648

(d) 39​- 59319

Step-by-step explanation:

a) (2x+1)+(2x+3)+(2x+5)=11³

or, 6x+9=1331

or, x=220.3≈220

now, 1st odd no.: 220×2+1=441

2nd odd no.:220×2+3=443

3rd no.:(we have taken x as approximate value to find an odd number)

so, third number=1331-(443+441)

=447

therefore: numbers are 441,443 and 447

b)(2x+1)+(2x+3)+(2x+5)+(2x+7)=14³

or 8x+16=2744

x=341

now, 1st odd no.: 341×2+1=683

2nd odd no.:341×2+3=685

3rd odd no.: 341×2+5=687

4th odd no.:341×2+7=689

so, 683+685+687+689= 2744

and so on