Question

If the roots of $x^2+8x+15=0$ are -3 and -5, then the roots of $6x^2+48x+90=0$ are .

• A. -3 and -5
• B. -30 and -50
• C. -18 and -30
• D. 3 and 5

Answer 1

The correct option is A -3 and -5

Given, the roots of $x^2+8x+15$ = 0 are -3 and -5.
The equation $6x^2+48x+90$ = 0 can be written as
6$\times$($x^2+8x+15$) = 0
$\Rightarrow$ $x^2+8x+15$ = 0.
Hence, the roots of $6x^2+48x+120$ = 0 are -3 and -5.
The roots of a quadratic equation do not change when it is multiplied by a constant non-zero real number.