In the [tex]$xy$[/tex]-plane, the slope of the line [tex]$y = mx - 4$[/tex] is less than the slope of the line [tex]$y = x - 4$[/tex]. Which of the following must be true about [tex]$m$[/tex]?

A. [tex]$m = -1$[/tex]
B. [tex]$m = 1$[/tex]
C. [tex]$m \ \textless \ 1$[/tex]
D. [tex]$m \ \textgreater \ 1$[/tex]



Answer :

To solve this problem, we need to compare the slopes of two different lines and determine the constraints on [tex]\( m \)[/tex], based on the condition given in the question.

1. Understand the problem:
- We have two lines in the [tex]\( xy \)[/tex]-plane:
- Line 1: [tex]\( y = mx - 4 \)[/tex]
- Line 2: [tex]\( y = x - 4 \)[/tex]
- We need the slope of Line 1 to be less than the slope of Line 2.

2. Identify the slopes:
- The slope of Line 1 is [tex]\( m \)[/tex].
- The slope of Line 2 is [tex]\( 1 \)[/tex] (since it's in the form [tex]\( y = mx + c \)[/tex] and [tex]\( m \)[/tex] is the coefficient of [tex]\( x \)[/tex]).

3. Set up the inequality:
- We need the slope of Line 1 to be less than the slope of Line 2.
- Therefore, [tex]\( m < 1 \)[/tex].

4. Analyze the given choices to determine which values satisfy [tex]\( m < 1 \)[/tex]:

- [tex]\( m = -1 \)[/tex]: This value is less than 1, so it satisfies the inequality [tex]\( m < 1 \)[/tex].
- [tex]\( m = 1 \)[/tex]: This value is not less than 1; it is equal to 1, so it does not satisfy the inequality.
- [tex]\( m < 1 \)[/tex]: This is a direct expression of the inequality we need, so it is correct.
- [tex]\( m > 1 \)[/tex]: This value does not satisfy the inequality since it is greater than 1.

Therefore, the values from the provided choices that must be true about [tex]\( m \)[/tex] are:
[tex]\[ m = -1 \][/tex]
[tex]\[ m < 1 \][/tex]

Additionally, if we need specific examples of [tex]\( m \)[/tex] that satisfy this inequality from a provided list of numerical values, we would find that:

- [tex]\( m = -1 \)[/tex]: satisfies [tex]\( m < 1 \)[/tex]
- [tex]\( m = \frac{999}{1000} \)[/tex]: satisfies [tex]\( m < 1 \)[/tex] (since [tex]\( \frac{999}{1000} \approx 0.999 \)[/tex])

So, the correct values of [tex]\( m \)[/tex] are:
[tex]\[ m = -1 \][/tex]
[tex]\[ \frac{999}{1000} < 1 \text{ (which is approximately 0.999) } \][/tex]

Summing up, the final values satisfying [tex]\( m < 1 \)[/tex] are:
[tex]\[ -1 \][/tex]
[tex]\[ \frac{999}{1000} \][/tex]