Question

18. If the product of zeroes of ax2 – 6x – 6 is 4 find the value of a. Hence find the sum of its zeroes.

Answer 1

Answer:

Step-by-step explanation:

Given c/a=4

so, -6/a=4

a=-6/4

=-2/3

sum=-b/a

-(-6)/-2/3= -18/2=-9

hope it helps..

Answer 2

$\large{\underline{\bf{Explanation-}}}$

Given polynomial : ax² - 6x - 6

comparing it to ax² + bx + c

a = a

b = -6

c = -6

Product of zeroes = $\dfrac{c}{a}$

$\implies$ Product of zeroes = $\dfrac{-6}{a}$

Also, it is given that product of zeroes = 4

$\therefore$ 4 = $\dfrac{-6}{a}$

$\implies$ 4a = -6

$\implies$ a = $\dfrac{-6}{4}$

$\implies$ a = $\dfrac{-3}{2}$

$\rule{200}2$

Now, putting the value of a in the given polynomial,

$\implies$ $\dfrac{-3}{2}$ x² - 6x - 6 = 0

Taking LCM,

$\implies$ -3x² -12x - 12 = 0

Taking 3 as common,

$\implies$ -x² - 4x - 4 = 0

Sum of zeroes = $\dfrac{-b}{a}$

$\implies$ Sum of zeroes = $\dfrac{-(-4)}{-1}$

$\implies$ Sum of zeroes = -4