Question

Without actually calculating the cube find the value of (5)^3 + (2)^3 + (-7)^3 also write the identity used

Answer 1

(5)³ + (2)³ + (-7)³
a³+b³ = (a+b) ³-3ab(a+b)

Answer 2

Step-by-step explanation:(5)^3 + (2)^3 + (-7)^3

using formula (x)^3 + (y)^3 + (z)^3 - 3xyz = (x+y+z) (x)^2 + (y)^2 + (z)^2

check whether x+y+z=0 --> 5+2-7=0

there fore (5)^3 + (2)^3 + (-7)^3 = 3xyz

                                                     = 3*5*2*-7    => -210

                  hope it helps