Question

Without actual calculating the cubes the value of 28^3+ (–15)^3+(–13)^3

is:

(a) 16380 (b) –16380 (c) 15380 (d) –15380​

Answer 1

Step-by-step explanation:

(a) 16380

process

(28)^3-(15)^3-(13)^3

21,952 - 3,375 - 2,197

16,380

Answer 2

We know the formula, a^3 +b^3 + c^3=3abc, when (a+b+c)=0

Here let's calculate a+b+c, first.

a=28

b=-15

c=-13

and so, the sum will be zero.

so the answer is 3abc

that is, 3 x 28 x 195(195 will be positive product of two negative multiples, 15 and 13(

=84 x 195

=16575