Find the Cube Of: 3 a + 1 3 a

Find the cube of: `3"a" + (1)/(3"a")`

Sum

`(3"a" + 1/(3"a"))^3`

= `(3"a")^3 + (1/(3"a"))^3 + 3 (3"a") (1/(3"a")) (3"a" + 1/(3"a"))`

= `27"a"^3 + (1)/(27"a"^3) + 9"a" + (1)/"a"`.

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Chapter 3: Expansions - Exercise 4.2

Chapter 3 Expansions
Exercise 4.2 | Q 1.3

If `a^2 + 1/a^2` = 18; a ≠ 0 find :

(i) `a - 1/a`

(ii) `a^3 - 1/a^3`

If 4x²+ y²= a and xy = b, find the value of 2x + y.

The sum of two numbers is 9 and their product is 20. Find the sum of their (i) Squares (ii) Cubes.

If 2x - 3y = 10 and xy = 16; find the value of 8x³ - 27y³.

If a ≠ 0 and `a - 1/a` = 4 ; find : `( a^4 + 1/a^4 )`

Find the cube of: 2a - 5b

Find the cube of: `"a" - (1)/"a" + "b"`

If a + b + c = 0; then show that a³ + b³ + c³ = 3abc.

Expand (3p + 4q)³

Find the volume of the cube whose side is (x + 1) cm