Question

If (2x-1/2)=12then find the value of 8x3+1/8x3

Answer 1

2x - 1/2 = 12
2x = 12 + 0.5
x = 12.5/2

x = 6.25 = 25/4

so
8x³ + 1/8x³
= (2x)³ + 1/(2x)³
= (25/2)³ + (2/25)³
= 15625/8 + 8/15625

= [244140625 + 64] ÷ [8×15625]
= 244140689 ÷ 125000

= 1953.12551

Answer 2

Hey freind here is ur answer,

2x - 1 / 2 = 12
Taking L.C.M = 2
2x * 2 / 2 - 1 / 2 = 12
4x / 2 - 1 / 2 = 12
4x - 1 = 12 * 2
4x = 24 + 1
x = 25 / 4

Finding value of 8x³ + 1 / 8 x³

value of x³ = ( 25 / 4 ) ³
= 25 * 625 / 64
= 15625 / 64

So value of 8x³ = 8 * x³
= 8 * 15625 / 64
= 15625 / 8

So now value of 1 / 8 x³ = 1 / 8 * x³
= 1 / 8 * 15625 / 64
= 15625 / 512

so now value of 8x³ + 1 / 8 x³
8x³ + 1 / 8 x³ = 15625 / 8 + 15625 / 512
Taking L.C.M = 512
15625 / 8 * 64 / 64 + 15625 / 512
1000000 / 512 + 15625 / 512
1015625 / 512
=1983.64 ( approx. )

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Hope it helps