Question

how to solve question 21

Answer 1

(2acuberoot)^3-(4bcuberoot)^3-(c cube root)^3=24abc cube root

if a=b=c then
(2acuberoot)^3-(4acuberoot )^3-(acuberoot)^3=24a
=》8a-64a-a=24a
=》-57a=24a this is not possible

if a+b+c=0
8a-64b-c=24abc cuberoot



i don't know then

Answer 2

$8a - 64b - c = 24 \sqrt[3]{abc} \\ = > ({2} { \sqrt[3]{a} })^{3} - ({4} { \sqrt[3]{b} })^{3} - ({ \sqrt[3]{c} })^{3} = 3 \times (8 \sqrt[3]{abc}) \\ \\ we \: know \: that \: if \: \: \: \\ {a}^{3} + {b}^{3} + {c}^{3} = 3abc\: \\ then \\a + b + c \: = 0 \\ \\ use \: it \: here.. \\ we \: get \: ({2} { \sqrt[3]{a} }) - ({4} { \sqrt[3]{b} }) - ({ \sqrt[3]{c} }) = 0$