Answer:
One.
Explanation:
This polynomial has only one variable, which is x*. We can treat z and 7 as constants. Therefore, the polynomial is linear and can be written as:
5x* + c
where c = 7 - 3z.
A linear polynomial has either one root (when the coefficient is non-zero) or zero roots (when the coefficient is zero). Therefore, the given polynomial has exactly one root, which is:
x* = -c/5 = -(7 - 3z)/5 = (3z - 7)/5