Which expression is a sum of cubes?

We have been given 4 expressions. We are asked to choose the expression that represents sum of cubes.

We know that sum of cubes is in form .

We can see that 1st and 2nd option has a negative sign. Therefore, these options cannot be sum of cubes.

Let us check 3rd and 4th options one by one.

We can rewrite our expression by writing terms as cubes:

Therefore, expression is a sum of cubes.

In 4th expression, we can see that . We cannot represent it as a cube. Similarly, we cannot represent as a cube. Therefore, 4th expression is not correct.

the answer is b: 18

step-by-step explanation:

use the pythagorean theorem to .

a^2+b^2=c^2

plug 18 for "r"

the 2 legs are 18 and 24

18^2+24^2=c^2

324+576=c^2

900=c^2

c=30

30-12=18

18 is the radius

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