Find the value of x 3 +y 3 -12xy+64,when x+y=-4
Answers
Answered by
6
x³ + y³ - 12xy + 64
x + y = - 4 ................( i )
(i) .... cubing both sides
x³ + y³ + 3xy(x + y) = - 4
⇒ x³ + y³ + 3xy( - 4) = - 4
⇒ x³ + y³ - 12xy = - 4
so the value of x³ + y³ - 12xy + 64 = 64 - 4 = 60 ANSWER
x + y = - 4 ................( i )
(i) .... cubing both sides
x³ + y³ + 3xy(x + y) = - 4
⇒ x³ + y³ + 3xy( - 4) = - 4
⇒ x³ + y³ - 12xy = - 4
so the value of x³ + y³ - 12xy + 64 = 64 - 4 = 60 ANSWER
Similar questions