Question

without finding the cubes factorise (13)³ + (-8)³ + (-5)³ / (12)³ + (-8)³ + (-4)³

Answer 1

Step-by-step explanation:

13³ + (-5)³ + (-8)³ / 12³ + (-8)³ + (-4)³

Now, 13 + (-5) + (-8) = 0 and 12 + (-8) + (-4) = 0

Using identify,

(a+b+c)(a²+b²+c² -ab - bc - ca)= a³+b³+c³ - 3abc

if a+b+c = 0 then a³+b³+c³ = 3abc

13*8*5 / 12*8*4

= 65 / 48