Question

if a+b+c =5 then show that; a³+8b³+30ab=125​

Answer 1

Step-by-step explanation:

Your question needs to be corrected. It should be,

If a+2b = 5, then prove that, a³+8b³+30ab=125​

now, solution,

take, a+2b = 5

=> (a+2b)³ = 5³

=> a³ + (2b)³ + 3*a*2b(a+2b) = 125

=> a³ + 8b³ + 6ab(5) = 125     (given a+2b = 5 )

=> a³ + 8b³ + 30ab = 125  , which is the required equation to be proved

Hence proved