One root of the quadratic equation ax2 bx c 0 is 2 and one root of the quadratic equation cx2 b...........

Quantitative Aptitude (CGL) Algebra

One root of the quadratic equation ax²+bx+c=0 is 2 and one root of the quadratic equation cx²+bx+a=0cx2+bx+a=0 is −1/3. What is the sum of the roots of the first equation?

5/3

-1

-2

-3

छोटे Courses बड़े Results

Master Algebra

Prepare through Micro-courses

Try Now

Explanation:

Let m be the second root of first equation and n be the second root of second equation
For First Equation
Sum of roots = -(b/a)
so, m+2 = -(b/a) ------------ (1)
Product of roots = c/a
so, 2m = c/a ---------------(2)
For Second Equation
Sum of roots = -(b/c)
so, m+2 = -(b/c) ------------ (3)
Product of roots = a/c
so, 2m = a/c ---------------(4)
Multiply (2) and (4) and we get m*n = -(3/2)
Multiply (2) and (3) and we get
-(b/a) = (2m)*(n-1/3)
Now -(b/a) = m+2
So, m+2 = (2m)(n-1/3)
we have value of mn so value of m can be obtained from above equation.
m = -3
Sum of roots of first equation = -3+2 = -1