Equation of line joined by (-1, 1) (2, 7)
\(\frac{y-1}{x+1}=\frac{7-1}{2+1}\)
\(\frac{y-1}{x+1}=\frac{6}{3}=2\)
y - 1 = 2(x + 1)
y = 2x + 2 + 1 = 2x + 3
y = 2x + 3
Slope of line joined by (-1,1), (x, 2x + 3)
= \(\frac{2x+3-1}{x+1}=\frac{2x+2}{x+1}\) = 2
Slope of line joined by (2, 7), (x, 2x + 3)
\(=\frac{2x+3-7}{x-2}=\frac{2x-4}{x-2}=2\)
The slopes are same hence die point (x, 2x + 3) is passing through the points (–1, 1), (2, 7)
