Question

If -5 is one of the root of 2 x square + p x minus 15 quadratic polynomial p x square + x + k has both the zeros equal to each other find k

Answer 1

Answer:

1/28

Step-by-step explanation:

If -5 is one of the root of 2 x square + p x minus 15 quadratic polynomial p x square + x + k has both the zeros equal to each other find k

-5 is one root of

2x² + px - 15

roots =  (- p ± √(p² - 4(2)(-15) )/(2×2)

(- p ± √(p² + 120 ))/(2×2) = - 5

=> -p ± √(p² + 120 ) = - 20

=> ± √(p² + 120 ) = p - 20

Squaring both sides

p² + 120 = p² + 400 - 40p

=> 40p = 280

=> p = 7

px² + x + k

= 7x² + x + k

both roots are equal

1² = 4×7×k

=> k = 1/28