Question

If 12x2 - ax + 7 = ax2 + 9x + 3 has only one (repeated) solution, then the positive integral solution of a is:

Answer 1

Answer:

a = 3

Step-by-step explanation:

If 12x2 - ax + 7 = ax2 + 9x + 3 has only one (repeated) solution, then the positive integral solution of a is:

12x² - ax + 7 = ax² + 9x + 3

=> x²(12-a)  - (9 + a)   + 4 = 0

to have only one solution D = 0

(9 + a)² = 4(12-a)(4)

=> 81 + a² + 18a  =  192 - 16a

=> a² + 34a - 111 = 0

=> a² + 37a - 3a - 111 = 0

=> a(a + 37) - 3(a + 37) = 0

=> (a -3)(a + 37) = 0

a = 3  & a = -37

-37 is not +v3

so a = 3