Question

if -5 is a root of the equation 2 X square + p x minus 15 is equals to zero then find the other route​

Answer 1

Let m , n are two roots of

given Quadratic equation.

m = -5 ,

Compare 2x²+px-15=0 with

ax²+bx+c=0, we get

a = 2 , b = p , c = -15

Product of the roots = c/a

=> mn = (-15)/2

=>(- 5n ) = (-15)/2

=> n = ( -15 )/[(-5)×2]

= 3/2

Therefore,

Other root = n = 3/2

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Answer 2

$2 {x}^{2} + px - 15 = 0 \: \: has \: \: root \: - 5 \\ then \: 2 { (- 5)}^{2} - 5p - 15 = 0 \\ = > 50 - 5p - 15 = 0 \\ = > p = 7 \\ so \: our \: quadratic \: eqn \: becomes \: \\ 2 {x}^{2} + 7x - 15 = 0 \\ \\ = > x = (- 7 + \sqrt{49 + 120} ) \div 4 \\ and \: x =( - 7 - \sqrt{49 + 120} ) \div 4$