Graph [tex]$y = -3x + 6$[/tex] using the interactive graphing calculator.

Which of the following statements are true?

A. The line increases from left to right.
B. The line crosses the [tex]$x$[/tex]-axis at -3.
C. The line crosses the [tex]$y$[/tex]-axis at 6.
D. As the input increases, the output decreases.
E. The line does not enter quadrant II at all.
F. The point [tex]$(3.5, -4.5)$[/tex] lies on the line.



Answer :

To analyze the line given by the equation [tex]\( y = -3x + 6 \)[/tex], let's evaluate each statement one by one.

### Statement 1: The line increases from left to right

To determine if the line increases or decreases, we look at the slope. The slope [tex]\( m \)[/tex] in the equation [tex]\( y = mx + b \)[/tex] is the coefficient of [tex]\( x \)[/tex]. Here, [tex]\( m = -3 \)[/tex], which is a negative value. A negative slope indicates that the line decreases from left to right, not increases.

Conclusion: This statement is false.

### Statement 2: The line crosses the x-axis at -3

To find the x-intercept of a line, we set [tex]\( y = 0 \)[/tex] and solve for [tex]\( x \)[/tex]:

[tex]\[ 0 = -3x + 6 \implies 3x = 6 \implies x = 2 \][/tex]

The line crosses the x-axis at [tex]\( x = 2 \)[/tex], not at -3.

Conclusion: This statement is false.

### Statement 3: The line crosses the y-axis at 6

To find the y-intercept, we set [tex]\( x = 0 \)[/tex] and solve for [tex]\( y \)[/tex]:

[tex]\[ y = -3(0) + 6 \implies y = 6 \][/tex]

The line crosses the y-axis at [tex]\( y = 6 \)[/tex], which is correct.

Conclusion: This statement is true.

### Statement 4: As the input increases, the output decreases

As [tex]\( x \)[/tex] (the input) increases, we need to determine what happens to [tex]\( y \)[/tex] (the output). With a negative slope of -3, as [tex]\( x \)[/tex] increases, [tex]\( y \)[/tex] decreases. This is due to the negative relationship described by the slope.

Conclusion: This statement is true.

### Statement 5: The line does not enter quadrant II at all

Quadrant II is where [tex]\( x \)[/tex] is negative and [tex]\( y \)[/tex] is positive. We need to check if the line ever passes through this quadrant. For [tex]\( x \)[/tex] values less than 0:

[tex]\[ y = -3x + 6 \][/tex]

If [tex]\( x \)[/tex] is negative, then [tex]\( -3x \)[/tex] becomes positive, making [tex]\( y \)[/tex] greater than 6, which is positive. Therefore, the line does enter quadrant II.

Conclusion: This statement is false.

### Statement 6: The point [tex]\((3.5, -4.5)\)[/tex] lies on the line

To verify if the point [tex]\((3.5, -4.5)\)[/tex] lies on the line, we substitute [tex]\( x = 3.5 \)[/tex] into the equation and see if [tex]\( y \)[/tex] equals [tex]\(-4.5\)[/tex]:

[tex]\[ y = -3(3.5) + 6 = -10.5 + 6 = -4.5 \][/tex]

Since the calculated [tex]\( y \)[/tex] value matches the given [tex]\( y \)[/tex] value, the point [tex]\((3.5, -4.5)\)[/tex] lies on the line.

Conclusion: This statement is true.

### Summary
After evaluating each statement, the true statements are:

- The line crosses the y-axis at 6.
- As the input increases, the output decreases.
- The point [tex]\((3.5, -4.5)\)[/tex] lies on the line.

Thus, the true statements are:

[tex]\[ \text{True statements: (c), (d), (f)} \][/tex]

False statements:

- (a) The line increases from left to right.
- (b) The line crosses the [tex]\( x \)[/tex]-axis at -3.
- (e) The line does not enter quadrant II at all.