Question

Q7: Find the value of a if 9x² - 7x + a is equal to 6 for x = 1.​

Answer 1

Step-by-step explanation:

Since, 9x

2

+6kx+4=0 has equal roots.

Then, b

2

−4ac⩾0

(6k)

2

−4(9)(4)⩾0

36k

2

−36(4)⩾0

36(k

2

−4)=0

k

2

−4=0

k

2

=2

2

k=±2

Let us check

9x

2

+6(2)x+4=0

9x

2

+12x+4=0

9x

2

+6x+6x+4=0

3x(3x+2)+2(3x+2)=0

(3x+2)(3x+2)=0

∴x=

3

−2

,

3

−2