Question 66390
The values of x that must be excluded are those values that would make the denominator equal zero.
Why is that important?
Because, in mathematics, division by zero is undefined! In other word it doesn't make sense, mathematically.
{{{(x-3)/(4x-5)(x+1)}}}
So, in the denominator we have:
{{{(4x-5)*(x+1)}}} Let's take these factors one-at-a-time.
{{{4x-5)}}} To find the value of x that would make this equal zero, we just set this factor equal to zero and solve for x.
{{{4x-5 = 0}}} Add 5 to both sides.
{{{4x = 5}}} Now divide both sides by 4.
{{{x = 5/4}}} This is one of the excluded values of x! We can find the other one  by doing the same thing with the other factor.
{{{x+1 = 0}}} Subtract 1 from both sides.
{{{x = -1}}} This is the other excluded value of x.