Question

If 2x +3y=12 and xy=6,find the value of 8x^3+27y^3

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Answer 1

Step-by-step explanation:

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