Question

Out of the following equations, find the equation having the sum of its roots -5.
(A) 3x²-15x+3=0
(B) x²-5x+3=0
(C) x²+3x-5=0
(D) 3x²+15x+3=0

Answer 1

we know, if ax² + bx + c = 0 is general form of quadratic equation where a ≠ 0 then,
sum of roots = - coefficient of x/coefficient of x²

Here,
sum of roots = -5 = -coefficient of x/coefficient of x²
Let's check all of options :
(A) 3x² - 15x + 3 = 0
sum of roots = -coefficient of x/coefficient of x²
= -(-15)/3 = 5
hence, sum of roots ≠ - 5

(B) x² - 5x + 3 = 0
sum of roots = - coefficient of x/coefficient of x²
= - (-5)/1 = 5
hence, sum of roots ≠ -5

(C) x² + 3x - 5 = 0
sum of roots = - coefficient of x/coefficient of x²
= -3/1 = -3
hence, sum of roots ≠ -5

(D) 3x² + 15x + 3 = 0
sum of roots = - coefficient of x/coefficient of x²
= -(15)/3 = -5
hence, sum of roots = -5

hence, option (d) is correct

Answer 2

Step-by-step explanation:

use this.

It may help you.