Answer:
3x - 4y - 7 = 0
Explanation:
We know that the equation of a straight line passing through two known points
and
is given by

Therefore, the equation of the straight line passing through the points (21,14) and (49,35) will be

⇒

⇒ 4(y - 35) = 3(x - 49)
⇒ 4y - 140 = 3x - 147
⇒ 3x - 4y - 7 = 0 (Answer)