Question

017:) Ifa and are the zeroes of quadratic polynomial x- kx + 15 such that (a + b)2-2aß = 34, find k.​

Answer 1

Hey!

Given Equation :- x² - kx + 15
Given Condition :- ( a + b )² - 2ab = 34


• Sum of Zeros =



a + b = k/1


• Product of Zeros =



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 !!

Answer 2

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 !!