If 2x + 3y = 13 and xy = 6, then the value of 8x3 + 27y3 is ___________?
Answers
Answered by
439
2x +3y = 13-----(1)
xy =6-----(2)
8x³ +27y³
= (2x)³ +(3y)³
= (2x+3y)³ - 3*2x*3y(2x+3y) [using (a+b)³ = a³+b³+3ab(a+b)]
= (13)³- 18 * 6 *13 [ using (1) and (2)]
= 2197 - 1404
=793
xy =6-----(2)
8x³ +27y³
= (2x)³ +(3y)³
= (2x+3y)³ - 3*2x*3y(2x+3y) [using (a+b)³ = a³+b³+3ab(a+b)]
= (13)³- 18 * 6 *13 [ using (1) and (2)]
= 2197 - 1404
=793
Answered by
114
Answer:793
Step-by-step explanation:
Using identity {x+y}^3
(2x+3y)^3-3×2x×3y{2x+3y}
{13}^3-18×6×13
2197-1407
Ans=
793
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