P =\(\left(x^3+3x^2+3x+1\right)+3\left(x^2+2x+1\right)y+3\left(x+1\right)y^2+y^3\)
= \(\left(x+1\right)^3\)+ 3\(\left(x+1\right)^2\)y + 3.(x + 1)\(y^2\) + \(y^3\)
= \(\left(x+y+1\right)^3\) = \(\left(9+1\right)^3\) = \(10^3\) = 1000
M=\(\left(x+y\right)^3+2\left(x^2+2xy+y^2\right)\)
=\(\left(x+y\right)^3+2\left(x+y\right)^2\)
= \(\left(x+y\right)^2\left(x+y+2\right)\)
= \(7^2\left(7+2\right)\) = 49.9 = 441
N = \(\left(x-y\right)^3-\left(x^2-2xy+y^2\right)\)
= \(\left(x-y\right)^3-\left(x-y\right)^2\)
= \(\left(x-y\right)^2\left(x-y-1\right)\)
= \(\left(-5\right)^2\left(-5-1\right)\)
= 25. (-6) = (-150)
