Question

The equation of the straight line which passes through the point P (3, 4) and whose intercept on y-axis is twice of that on x-axis, is .

• A. $2x–y=10$
• B. $x+2y=10$
• C. $2x+y=10$
• D. $3x-4y+7=0$

Answer 1

The correct option is C $2x+y=10$

Let the x-intercept = a and the y-intercept = 2a.
Therefore the line passes through the points A (a, 0) and B (0, 2a).

Slope of the line = $\frac{2a-0}{0-a|}$ = -2

We know that the line passes through P (3, 4)

Therefore the equation of the line, using point slope form is
y - 4 = -2 (x - 3)
y - 4= -2x + 6
2x + y = 10