Answer:
The value of [tex]8\cdot x^{3} + 27\cdot y^{3}[/tex] is 432.
Step-by-step explanation:
Let be the following system of equations:
[tex]2\cdot x + 3\cdot y = 12[/tex] (1)
[tex]x\cdot y = 6[/tex] (2)
Then, we solve both for [tex]x[/tex] and [tex]y[/tex]:
From (1):
[tex]2\cdot x + 3\cdot y = 12[/tex]
[tex]2\cdot x = 12- 3\cdot y[/tex]
[tex]x = 6 - \frac{3}{2}\cdot y[/tex]
(1) in (2):
[tex]\left(6-\frac{3}{2}\cdot y \right)\cdot y = 6[/tex]
[tex]6\cdot y-\frac{3}{2}\cdot y^{2} = 6[/tex]
[tex]\frac{3}{2}\cdot y^{2}-6\cdot y + 6 = 0[/tex]
The roots of the polynomial are determined by the Quadratic Formula:
[tex]y_{1} = y_{2} = 2[/tex]
By (1):
[tex]x = 6 - \frac{3}{2}\cdot (2)[/tex]
[tex]x = 3[/tex]
If we know that [tex]x = 3[/tex] and [tex]y = 2[/tex], then the final value is:
[tex]z = 8\cdot x^{3}+27\cdot y^{3}[/tex]
[tex]z = 8\cdot 3^{3}+27\cdot 2^{3}[/tex]
[tex]z = 432[/tex]
The value of [tex]8\cdot x^{3} + 27\cdot y^{3}[/tex] is 432.
