Question

if x squared plus y squared equal to 49 and x minus y equal to 3 then find the value of x cube minus y cube

Answer 1

x²+y² = 49

x-y = 3

Now , ( x - y) ² = x²+y²-2xy

3² = 49 - 2xy.

2xy = 49 - 9 = 40

xy = 40/2 = 20 .

Now (x-y)³ = x³-y³-3xy(x-y)

3³ = x³-y³ - 3(20)(3)

3³ = x³-y³ - 180

27 + 180 = x³ - y³

x³ - y³ = 207 .

Hope helped! ^^

Answer 2

Answer:

(x-y)²=x²+y²-2xy

3²=49-2xy

9=49-2xy

9-49 = 2xy

-40 = 2xy

-40/2 =xy

-20 = xy

xy = 20

therefore

(x-y)³ = x³-y³- 3xy( x- y)

3³ =x³-y³-3×20×3

27 = x³ - y³ - 180

x³ + y³ = -180-27

x³+y³ = -207

this is your answer I hope it help you