KVPY2011MathematicsStraight Lines
Let A=(4,0), B=(0,12) be two points in the plane. The locus of a point C such that the area of triangle A B C is 18 sq. units is -
Options
- A(y+3 x+12)²=81
- B(y+3 x+81)²=12
- C(y+3 x-12)²=81
- D(y+3 x-81)²=12
Correct answer
C. (y+3 x-12)²=81
Step-by-step solution
1 2 | array ccc 1 & x & y 1 & 0 & 12 1 & 4 & 0 array |= 181(-48)-x(-12)+y(4)= 3612 x+4 y-48= 363 x+y-12= 9(3 x+y-12)²=81