Question

if x+3y=5 , provw that x³+27y³+45xy=125​

Answer 1

Step-by-step explanation:

since, (a+b)^3 = a^3 +b^3 + 3ab(a+b)

therefore, (x+3y)=5

or, (x+3y)³3 = 5³ (cubing both side)

or, x³ + 27y³ + 3x(3y)(x+3y) = 125

or, x³ + 27y³ + 9xy*5= 125 ( given x+3y = 5)

or, x³ + 27y³ + 45xy = 125 (proved)