Question

Find the equation of a straight line passing through the points (1, 1) and (2, -1)

Answer 1

The equation of a line with slope a and y-intercept b can be expressed in the for y = ax + b.

For a line passing through the points (1,1) and (2,-1), its slope is given by:

`a=((-1)-1)/(2-1)=-2`

To find the intercept, we can just replace x and y by one of the given pairs of coordinates:

`\begin{gathered} y=-2x+b \\ 1=(-2)\cdot1+b \\ b=1+2 \\ b=3 \end{gathered}`

Therefore, the equation of the line is y = -2x + 3