Question

(99.8)3 find the value using suitable identity

Answer 1

Answer:

(100-0.2)3

Step-by-step explanation:

identity used (a-b)3 = a3-b3-3ab(a-b)

1000000-0.008-6000+12

944011.92

Answer 2

Answer:

The value of  (99.8)³ = 994011.992

Step-by-step explanation:

To find,

The value of (99.8)³ using suitable identity

Solution:

Recall the identity

(a-b)³ = a³ - 3a²b+ 3ab²- b³

here 99.8 can be written as 99.8 = $\frac{99.8X10}{10}$ = $\frac{998}{10}$

(99.8)³ =$(\frac{998}{10})^3$ = $\frac{998^3}{10^3}$ = $\frac{998^3}{1000}$

Here 998 can be written as 998 = 100-2

Applying the identity (a-b)³ = a³ - 3a²b+ 3ab²- b³, here a = 1000 and b = 2 we get

998³ = (1000-2)³

= 1000³ - 3×1000²×2 + 3×1000×2² - 2³

= 1000000000 - 6×100000 +12×100 - 8

= 1000000000 - 6000000 +12000 - 8

= 1000000000 - 6000000 +12000 - 8

= 994011992

(99.8)³ = $\frac{994011992}{1000}$ = 994011.992

The value of  (99.8)³ = 994011.992

#SPJ2