The function $$y = {x^2}{e^{ - x}}$$ is decreasing in the interval

If R = {(x, y); x, y $$\in$$ Z, x² + y² $$\le$$ 4} is a relation in set Z, then domain of R is

The system of linear equations

5x + ky = 5,

3x + 3y = 5; will be consistent if

The equation of the tangent to the curve y (1 + x²) = 2 $$-$$ x, where it crosses the x-axis is