Question

find the equation of the line:
○$y = x - 1$
○$y=-\frac{1}{4}x - 1$
○$y = -\frac{3}{4}x - 1$
○$y=\frac{1}{2}x - 1$

Explanation:

Step1: Find the y - intercept

The line crosses the y - axis at $y=-1$, so the y - intercept $b=-1$.

Step2: Calculate the slope

Pick two points, say $(0, - 1)$ and $(4,-4)$. The slope $m=\frac{y_2 - y_1}{x_2 - x_1}=\frac{-4-(-1)}{4 - 0}=\frac{-4 + 1}{4}=-\frac{3}{4}$.

Step3: Write the equation

The slope - intercept form of a line is $y=mx + b$. Substituting $m =-\frac{3}{4}$ and $b=-1$ gives $y=-\frac{3}{4}x-1$.

Answer:

C. $y =-\frac{3}{4}x - 1$