Question

Find the value of (-7)³ + (12)³ + (-5)³ by using appropriate identity.

Answer 1

Answer:

-343+1728-125

-343+1603

=1260

Answer 2

Answer:

The value is 1260.

Step-by-step explanation:

As per the question,

We have to find the value of $(-7)^{3} + (12)^{3}+ (-5)^{3}$.

According to the cubic identity we know that,

$a^{3}+b^{3} = (a+b)(a^{2}-ab+b^{2})$

$a^{3}-b^{3} = (a-b)(a^{2}+ab+b^{2})$

Using this identity in the given question,

$(-7)^{3} + (12)^{3}+ (-5)^{3})$

$(-7+12)((-7)^{2}-(-7)(12)+12^{2})+(-5)^{3}$

$5(144+84+49)+(_5)^{3}$

$5(277-25)$

$1260$

Hence, the value is 1260.