The slope m of a line
through points \(A(x_1, y_1)\) and \(B(x_2, y_2)\) is given by :
\(\displaystyle{m = \frac{y_2-y_1}{x_2-x_1}\)
Thus, the slope of the line passing through points (−1, 7) and (2, 10) is
\(\displaystyle{m= \frac{10-7}{2-(-1)}= \frac{3}{3}=1\)
The equation of a line with slope m passing through a point P(a, b) is given by
(y-b)=m(x-a).
We can consider any of the points (-1, 7), or (2, 10). Let's choose (2, 10):
y-10=1(x-2)
y-10=x-2
y-x=-2+10
y-x=8
Answer: C. −x+y=8
