Daniel B. answered 01/09/21
A retired computer professional to teach math, physics
The general equation of a plane is of the form
ax + by + cz + d = 0
We are told that a = 7.
We are given three points, which we can plug in to get three equations for the three unknowns b, c, d:
-2×7 - 5×b + 0×c + d = 0
0×7 + 0×b + 3×c + d = 0
0×7 + 1×b + 5×c + d = 0
Solving them gives
b = -4
c = 2
d = -6
The equation of the plane is
7x - 4y + 2z - 6 = 0