Question

if a and b are the zeroes of the quadratic polynomial x2-kx+15 such that (a+b)^2 =34 dind the value of k​

Answer 1

Answer

Given Equation :- x² - kx + 15

Given Condition :- ( a + b )² - 2ab = 34

• Sum of Zeros =

= \frac{ - coefficient \: \: of \: \: x}{coefficien \: \: of \: \: {x}^{2} }=

coefficienofx

2

−coefficientofx

a + b = k/1

• Product of Zeros =

= \frac{constant \: \: term}{coeff. \: \: of \: {x}^{2} }=

coeff.ofx

2

constantterm

ab = 15

Now , from given condition :-

( a + b )² - 2ab = 34

( k )² - 2 × 15 = 34

k² - 30 = 34

k² = 34 + 30

k² = 64

k = √64

k = ± 8

So, the value of k is ±8 for the Equation !!