We can suppose the equation of the plane is in the form ...
ax +by +cz = 1
By using the given point coordinates for x, y, and z, we end up with three equations in 3 unknowns. These can be described by the augmented matrix ...
[tex] \left[\begin{array}{ccc|c}-2&-5&-4&1\\5&1&-4&1\\-1&2&5&1 \end{array}\right] [/tex]
Putting this in reduced row-echelon form, we find
a = 54/35
b = -63/35
c = 43/35
The equation of the plane through [tex]P_{0}(-2,-5,-4), Q_{0}(5,1,4), R_{0}(-1,2,5)[/tex] is ...
54x -63y +43z = 35
