Question

If a and b are zeroes of 2x²+5x+K,find K
if (a+b)whole square-ab=24.​

Answer 1

Dont copy answer cuz its not imported that my answer is correct but the way of doing the question is correct. I hope u understand the answer.

Best of Luck!

Answer 2

Let me take the zeroes as  α  and  β.

Consider a polynomial  p(x) = ax² + bx + c  whose zeroes are  α  and  β. Then,

→  α + β = -b/a

→  αβ = c/a

Let  p(x) = 2x² + 5x + k = 0.

A = 2   ;   B = 5   ;   C = k

Let the zeroes be  a  and  b.

a + b = -5/2   ;   ab = k/2

So, it may be,

(a + b)² - ab = 24

(-5/2)² - k/2 = 24

25/4 - 2k/4 = 24

(25 - 2k)/4 = 24

25 - 2k = 4 · 24

25 - 2k = 96

k = (25 - 96)/2

k =  - 71 / 2

Hence found!