If m and n m gt n are the roots of the equation 7 x 2a 2 3a2 5a 7x 23a where a gt 0 then what is 3m ...........

Quantitative Aptitude (CDS) Quadratic Equations

If m and n(m > n) are the roots of the equation 7(x + 2a)² + 3a² = 5a(7x + 23a)where a > 0, then what is 3m – n equal to

12a

14a

15a

18a

छोटे Courses बड़े Results

Master Quadratic Equations

Prepare through Micro-courses

Try Now

Explanation:

7(x + 2a)² + 3a² = 5a(7x + 23a)
⇒ 7(x² + 4a² + 4ax) + 3a² = 35ax + 115a²
⇒ x² − ax − 12a²=0
⇒ (x + 3a) (x − 4a) = 0
x = −3 and x = 4a
M and n are the roots of the given equation
Let m = 4a and n = −3a
Now, 3m − n = 3(4a) − (−3a) = 12a + 3a =15a