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JEE Mains · Maths · STD 11 - 9. straight line

If the orthocentre of the triangle formed by the lines \(y=x+1, y=4 x-8\) and \(y=m x+c\) is at \((3,-1)\), then \(\mathrm{m}-\mathrm{c}\) is :

  1. A 0
  2. B -2
  3. C 4
  4. D 2
Verified Solution

Answer & Solution

Correct Answer

(A) 0

Step-by-step Solution

Detailed explanation

Solve line PQ & QR Point \(\mathrm{Q}\left(\frac{1-\mathrm{c}}{\mathrm{m}-1}, \frac{1-\mathrm{c}}{\mathrm{m}-1}+1\right)\) \(m_{2 H}=\frac{\frac{1-c}{m-1}+2}{\frac{1-c}{m-1}-3}=\frac{1-c+2 m-2}{1-c-3 m+3}=-\frac{1}{4}\)…