Which of the following is an equation for the plane through the point (4,-1,5) and parallel to the xy-plane.

To find the equation for a plane, we need to know a point on the plane and the normal vector to the plane. In this case, we are given that the plane is parallel to the xy-plane, which means the normal vector will have a z-component of 0.

Using this information, let's find the normal vector first. Since the plane is parallel to the xy-plane, the normal vector should be perpendicular to the xy-plane, which means it will have a direction in the z-axis.

The general form of a plane equation is Ax + By + Cz + D = 0, where (A, B, C) is the normal vector to the plane.

Since the plane is parallel to the xy-plane, its normal vector will be (0, 0, 1), as it points in the positive z-direction.

Now that we have the normal vector, we can find the equation of the plane. Plugging in the values we have:

0x + 0y + 1z + D = 0

Simplifying the equation, we get:

z + D = 0

To find the value of D, we can substitute the coordinates of the given point (4, -1, 5) into the equation:

5 + D = 0

Solving for D, we get:

D = -5

Now we can substitute the value of D back into the equation:

z + (-5) = 0

Simplifying, we get:

z - 5 = 0

Therefore, the equation for the plane through the point (4, -1, 5) and parallel to the xy-plane is:

z - 5 = 0

The xy-plane is a plane that is parallel to the z-axis. This means that all points on the plane have a z-coordinate of 0.

To find the equation of a plane parallel to the xy-plane, we can set the z-coordinate of the point (4,-1,5) to 0. This gives us the equation:

(x, y, 0) = (4, -1, 5)

Simplifying, we get:

x = 4
y = -1

Therefore, the equation for the plane through the point (4,-1,5) and parallel to the xy-plane is x = 4 and y = -1.

To find the equation of a plane parallel to the xy-plane, we can use the standard form of the equation of a plane:

Ax + By + Cz + D = 0

Since the plane is parallel to the xy-plane, the z-component of the normal vector will be zero. The normal vector of the plane is the coefficients (A, B, C) in the equation.

Given the point (4, -1, 5) and that the plane is parallel to the xy-plane, we know that the z-component of the normal vector is 0. So, the equation for the plane will be of the form:

Ax + By + D = 0

To find the values of A, B, and D, we can substitute the x and y coordinates of the given point into the equation:

A(4) + B(-1) + D = 0

Simplifying this equation, we get:

4A - B + D = 0

Since we have 3 variables (A, B, and D), we need an additional equation to solve for them. However, the problem does not provide any additional information, so we cannot find a unique solution for the equation of the plane.