Question

If a and b are the zeros of polynomials 2 X square + 5 x + k such that a square + b square +ab =21/4 then k=? (a) 3 (b) -3 (c) 2 (d) -2

Answer 1

Step-by-step explanation:

2x²+5x+k=0

a+b=-5/2 and ab=k/2

Given:- a²+b²+ab=21/4

(a+b)²-ab=21/4

(-5/2)²-k/2=21/4

25/4-k/2=21/4

k/2=25/4-21/4

k/2=4/4=1

k=2