Question

For x = 3 and y = -2, verify that
(x-y)^3 = x^3 - y^3 - 3xy (x-y)

Answer 1

Answer:

Given,

x = 3

y = -2

Find,

Verify it (x-y)³ = x³ - y³ - 3xy (x-y)

Step-by-step explanation:

So,

x = 3 and y = -2, verify that (x-y)³ = x³ - y³ - 3xy (x-y)

We get,

=> (3-(-2))³ = 3³ -(-2)³ -3*3*(-2)(3-(-2))

Or. (3+2)³ = 27 -(-2)(-2)(-2) - (-18) (3+2)

Or. 5³ = 27-(-8) + 18 * 5

Or. 125 = 27 + 8 + 90

Or. 125 = 125

Hence,

(x-y)³ = x³ - y³ - 3xy (x-y) is verified for x = 3 and y = -2

Answer 2

Given

• x = 3
• y = -2

To verify

• (x - y)³ = x³ - y³ - 3xy (x - y)

Solution

• [3 - (-2)]³ = 3³ - (-2)³ - 3(3)(-2) (3 - (-2)
• [5]³ = 27 - (-8) - 3(3)(-2)(5)
• 125 = 27 + 8 + 90
• 125 = 125
• L.H.S = R.H.S

Learn these

• (a + b)³ = a³ + b³ + 3ab (a + b)
• (a - b)³ = a³ - b³ - 3ab (a - b)
• a³ - b³ = (a - b) (a² + b² + ab)
• a³ + b³ = (a + b) (a² + b² - ab)