Question

cho x-y=-5. tính N= (x-y)^3 -x^2+2xy-y^2

Answer 1

\(N=\left(x-y\right)^3-x^2+2xy-y^2\\ =\left(-5\right)^3-\left(x^2-2xy+y^2\right)\\ =\left(-125\right)-\left(x-y\right)^2\\ =\left(-125\right)-\left(-5\right)^2=\left(-125\right)-25=\left(-150\right)\)

Answer 2

Ta có : N=(x-y)³ - x²+2xy-y²

N= (x-y)³ - (x²-2xy+y²)

N=(x-y)³ - (x-y)²

N=(-5)³ - (-5)²

N= -125 + 25

N= -100