Question

find cube of
a)-0.16
b)-2/7
c)14

Answer 1

a) $(-0.16)^3 = (-0.16)\cdot(-0.16)\cdot (-0.16) = -\frac{16}{100}\cdot\frac{16}{100}\cdot\frac{16}{100}=$
$= -\frac{16^3}{100^3} = -\frac{2^{12}}{10^6} = -\frac{4\cdot 2^{10}}{10^6} = -\frac{4096}{1000000} = -0.004096$

b) $\left(-\frac{2}{7}\right)^3 = -\frac{2^3}{7^3} = -\frac{8}{343}$

c) $14^3 = (2\cdot 7)^3 = 2^3\cdot 7^3 = 8\cdot 343 = 2744$