Hello, sfspitfire23!
Did you make a sketch?
I did . . . and babytalked my way to the answer.
In a coordinate system, points $\displaystyle A(5,3),\;B(x, 4),\;C(3, 2)$ are collinear.
Find a value of $\displaystyle x.$ Code:
 B
 (x,4)*
 * :
 * :1
 A * :
 (5,3)o        +
 * : ?
 * :1
 c * :
 (3,2)o        +
 2

  +    +        +        +
 3 5
Going from $\displaystyle C$ to $\displaystyle A$, we move 2 units right and 1 unit up.
Going from $\displaystyle A$ to $\displaystyle B$, we move ? units right and 1 unit up.
It is obvious (I hope) that: .$\displaystyle ? \,=\,2$
Therefore: .$\displaystyle B(7,4)\,\text{ and }\,x = 7$