Question

if x=2y+6 then find value of
$x {3} - 8y {3} - 36xy - 216$
​

Answer 1

Answer:

Step-by-step explanation:

We have:

x - 2y - 6 = 0

Hence, x3 - 8y3 - 216 = 3(x)(-2y)(-6)

Using the identity: If a + b + c = 0, then a3 + b3 + c3 = 3abc

 

Therefore, we get,

x3 - 8y3 - 216 - 36xy = 0

 

2) Let p(x) = x4-a2x2+3x-a

It is given that (x - a) is a factor of p(x), therefore, p(a) = 0

Therefore, a4-a2a2+3a-a = 0  

a4-a4+3a-a = 0

2a = 0

or, a = 0