Question

Find the equation of line joining (3, 4) and (5, 8).

(a) y = 2x-1

(b) y = 2x+2

(c) y = 2x+1

(d) y = 2x-2

I got this question in semester exam.

My question is based upon General Equation of a Line in chapter Straight Lines of Mathematics – Class 11

Answer 1

Right choice is (d) y = 2x-2

The best I can explain: We know, equation of line joining two points (x1, y1) and (x2, y2) is given by

\(\frac{y-y1}{y2-y1} = \frac{x-x1}{x2-x1}\)

So, equation will be \(\frac{y-4}{8-4} = \frac{x-3}{5-3}\)

=>\(\frac{y-4}{4} = \frac{x-3}{2}\)

=>y-4 = 2x-6

=>y = 2x-2