Question

Find the value of x³ + y³ - 12xy + 64 when x + y = - 4

Answer 1

Value of $\bf {x}^{3} + {y}^{3}+4^3-12xy=0$ ,if x+y=-4.

Given:

• ${x}^{3} + {y}^{3}-12xy+64$
• $x+y=-4$

To find:

• Find the value of expression.

Solution:

Identity to be used:

If $\bf a+b+c=0$ then $\bf {a}^{3} + {b}^{3}+c^3=3abc$

Step 1:

Write the given term as shown below:

$x+y+4=0$

and

${x}^{3} + {y}^{3}+4^3-12xy... eq1$

Step 2:

As the condition shown in identity satisfy.

So,

Put the value of ${x}^{3} + {y}^{3}+4^3=12xy$ in eq1.

$12xy-12xy =0$

Thus,

Value of $\bf {x}^{3} + {y}^{3}+4^3-12xy=0$ ,if x+y=-4.

Answer 2

It is solved now brother Mark as brainlist and press thanks