Question

Which of the following are correct:

• A. The slope of a line passing through (1, 1 ) and (2, 2) is -1.
• B. The slope of a line passing through (3, 3 ) and (4, 4) is 1.
• C. The slope of a line parallel to X-axis is zero.
• D. The slope of a line parallel to X-axis is 1.

Answer 1

Answer: (B), (C)

The correct options are
B

The slope of a line passing through (3, 3 ) and (4, 4) is 1.

C

The slope of a line parallel to X-axis is zero.

The slope of a line passing through two points $(x_1,y_1)$ and $(x_2,y_2)$ is $\frac{y_2-y_1}{x_2-x_1}$.

The slope of a line passing through (1, 1 ) and (2, 2) is $\frac{2-1}{2-1}=1$.

The slope of a line passing through (3, 3 ) and (4, 4) is $\frac{4-3}{4-3}=1$.

The ordinates of points on a line parallel to X-axis are equal. If $(x_1,y_1)$ and $(x_2,y_2)$ are two points on the line, then $y_1=y_2$, $⟹y_2-y_1=0$. So the slope of the line is zero.