if 3 X + 2 y = 9 and xy = 3 find 27 x³+ 8y³
by the process
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1
Answer:
Correct option is
A
243
3x+2y=9
Cubing both sides,
(3x+2y)
3
=9
3
Applying the formula,
(a+b)
3
=a
3
+b
3
+3ab(a+b)
∴(3x)
3
+(2y)
3
+3×3x×2y×(3x+2y))=729
(3x)
3
+(2y)
3
+18×xy×(3x+2y)=729
Substituting, 3x+2y=9;xy=3
∴27x
3
+8y
3
+18×3×9=729
27x
3
+8y
3
=729−486=243
Answered by
1
so , the value of 27x^3 + 8y^3 is 243
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