Question

if one zero of quadratic polynomial 3x^2 -8x +2k+1 is 7 find the other and find k

Answer 1

Heya !!!

P(X) = 3X² - 8X + 2K +1

P(7) = 3 × (7)² - 8 × 7 + 2K + 1

=> 3 × 49 - 56 + 2K + 1 = 0

=> 147 - 56 + 2K +1 = 0

=> 92 + 2K = 0

=> 2K = -92

=> K = -92/2

=> K = -46



Putting the value of K in ,


3X² - 8X + 2K + 1


3X² - 8X + 2 × (-46) + 1


3X² - 8X - 92 + 1


3X² - 8X - 91


Here,


A = Coefficient of X² = 3


B = Coefficient of X = -8


and,


C = Constant term = -91

Let Alpha = 7


Sum of zeroes = -B/A

Alpha + Beta = -(-8)/3


7 + Beta = 8/3


Beta = 8/3 - 7

Beta = 8-21/3


Beta = -13/3


★ HOPE IT WILL HELP YOU ★

Answer 2

Hello friends!!

Here is your answer :

P(x) = 3x² - 8x + 2k + 1

Given, 7 is the root of the equation.

Therefore, P( 7 ) = 0

3(7)² - 8(7) + 2k + 1 = 0

3 × 49 - 56 + 2k + 1 = 0

147 - 56 + 2k + 1 = 0

148 - 56 + 2k = 0

92 + 2k = 0

2k = – 92

k = - 92 / 2

k = - 46

Now,

P(x) = 3x² - 8x + 2(-46) + 1

= 3x² - 8x - 92 + 1

= 3x² - 8x - 91

Given, zero ( alpha) = 7

Let another zero be beta.

a = coefficient of x² = 3

b = coefficient of x = -8

c = constant term = -91


Sum of Zeroes = - b/a

7 + beta = - (-8)/3

7 + beta = 8 / 3

Beta = 8/3 - 7

Beta = 8 - 21 / 3

Beta = - 13 / 3

Therefore,

k = - 46

Other zero = - 13/3

Hope it helps you.. ^_^

#Be Brainly