Find the value of x³+ y³+ 15xy – 125
if x + y = 5.
please help me
Answers
Answered by
0
Answer:
0
Step-by-step explanation:
(x+y)³=x³+y³+3xy(x+y)
5³=x³+y³+3xy×5=x³+y³+15xy
125=x³+y³+15xy
and 125-125=0
here's your answer
Answered by
0
Answer:
It is given that x + y = 5
Cubing both sides,
(x + y)3 = 125
x3 + y3 + 3x2y + 3xy2 = 125
x3 + y3 - 125 + 3xy(x + y) = 0
x3 + y3 - 125 + 3xy(5) = 0 (Since, x + y = 5)
x3 + y3 - 125 + 15xy = 0
Hence, the required value of the given expression is 0.
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