
In matrix form, this is

The coefficient matrix has determinant

so it has an inverse, which is

Multiply both sides by the inverse matrix:


so that
and
.
Using x for width (x/2)-4=18. completely solved x=44
In geometry,
A point represents a point
Two points define a line extended on both sides of the points.
Two points define a ray if it extends on only one side of either of the points.
Three or more than three points define a plane.
Now as far as a wall is considered, it is a flat surface on which we can plot infinite points.
Hence the wall represents a plane.
Option C) is the right answer.
The rule of exponential multiplication is (a^x)*(a^y)=a^(x+y)
using this with your expression, we can do
(10^1)*(10^3)*(10^2)=10^(1+3+2)=10^6
Final answer:
10^6 or 1 million
Hope I helped :)