Question

Which of the following are the correct properties of slope A.If two lines have the same slope, then they are the same line. B.The slope of a line that moves up from left to right is positive. C.A steep line has negative slope. D.Some lines have an undefined slope. E.The slope of a line is always positive.

Answer 1

B.The slope of a line that moves up from left to right is positive.

Explanation:

Slope is the ratio of vertical change to horizontal change. If a line moves up as x-values increase, then the signs of both changes are positive, and the slope is positive. This observation matches selection B.

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Comments on other choices

If a line is vertical, it will exhibit a vertical change with no horizontal change. The denominator of the ratio for slope will be zero. Division by zero is undefined, so we say the slope of a vertical line is "undefined."

Lines with the same slope will be parallel, if they're not the same line.

A line that moves down to the right has a negative change in its vertical coordinate for a positive change in its horizontal coordinate. The ratio of changes will have a negative sign. So, the slope of a line that moves down to the right is negative, not positive.