Question

Plsss answer this question

Answer 1

Answer:

1385

Step-by-step explanation:

 Given,

⇒ x - y = 5

   Cube on both sides:

⇒ ( x - y )^3 =  5^3

        ( x - y )^3 = x^3 - y^3 - 3xy( x - y )

⇒ x^3 - y^3 - 3xy( x - y ) = 125

        Given, x - y = 5   and  xy = 84

⇒ x^3 - y^3 - 3( 84 )( 5 ) = 125

⇒ x^3 - y^3 - 1260 = 125

⇒ x^3 - y^3 = 125 + 1260 = 1385

Answer 2

Solution

Given :-

• x - y = 5 ---------Equ(1)
• xy = 84 ----------Equ(2)

Find :-

• Value of x³- y³

Explanation

Using Formula

★ ( a - b)² = a² + b² - 2ab

★ (a³ - b³) = (a-b)(a² + b² +ab)

So, Squaring both side of equ(1)

==> ( x - y)² = 5²

==> x² + y² - 2xy = 25

Keep value by equ(2)

==> x² + y² = 25 + 2 × 84

==> x² + y² = 25 + 168

==> x² + y² = 193 ----------Equ(3)

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Now,

==> (x³ - y³) = (x-y)(x²+y²+xy)

keep Value by equ(1) , (2) & (3)

==> (x³ - y³) = (5) * (193 + 84)

==> (x³ - y³) = 5 * 277

==> (x³ - y³ ) = 1385

________________________

Hence

• Value of (x³ - y³) = 1385 .

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