Manipal MET2011MathematicsFunctions
If x is real, then the value of x^2+34 x-71 x^2+2 x-7 does not lie between
Options
- A8 and -5
- B0 and 9
- C-5 and 9
- D5 and 9
Correct answer
D. 5 and 9
Step-by-step solution
aligned & Let y= x^2+34 x-71 x^2+2 x-7 & x^2(y-1)+2(y-17) x+(71-7 y)=0 aligned For real values of x , its discriminant, D 0 4(y-17)^2-4(y-1)(71-7 y) 0 array ll & (y^2-34 y+289 ) & - (71 y-7 y^2-71+7 y ) 0 & y^2-14 y+45 0 & (y-5)(y-9) 0 & y 5 and y 9 array Hence, y does not lie between 5 and 9