Question

if x-y = 4 and xy=21 , then find the value of x³- y³

Answer 1

Put the values in formula of x3-y3 u will ge5 5he answer ok

Answer 2

Answer:

316

Step-by-step explanation:

$x - y = 4 \\ xy = 21 \\ \\ {(x - y)}^{3} = {x}^{3} - {y}^{3} - 3xy(x - y) \\ {4}^{3} = {x}^{3} - {y}^{3} - 3(21)(4) \\ 64 = {x}^{3} - {y}^{3} - (63 \times 4) \\ 64 = {x}^{3} - {y}^{3} - 252 \\ 64 + 252 = {x}^{3} - {y}^{3} \\ \underline{ \underline{ 316}} = {x}^{3} - {y}^{3}$