Answer:
1). Yes
2). Yes
3). No
Explanation:
1). y = 3
We can rewrite this equation in the slope-intercept form as,
y = 0.x + 3
Here, slope = 0
y-intercept = 3
Therefore, it's a linear relation.
YES.
2). 2x - 5y = 10
5y = 2x - 10
y =

Therefor, it's a linear function.
YES
3). y = x(x + 3)
y =x² + 3x
Since, this equation is a quadratic equation,
It's not a linear function.
NO