Find p such that px^2-12x+4=0 has only one solution.

Thank you!!!

2 answers

In quadratic equation:

a x ^ 2 + b x + c

value D = b ^ 2 - 4ac is called the discriminant.

When Discriminant is zero we get just one real solution.

p x ^ 2 - 12 x + 4 = 0

In this case :

a = p , b = - 12 , c = 4

D = b ^ 2 - 4 a c =

( - 12 ) ^ 2 - 4 * p * 4 =

144 - 16 p = 0 Add 16 p to both sides

144 - 16 p + 16 p = 0 + 16 p

144 = 16 p Divide both sides by 16

144 / 16 = p

9 = p

p = 9

p x ^ 2 - 12 x + 4 = 0

become:

9 x ^ 2 - 12 x + 4 = 0

By the way the solution is x = 2 / 3
the answer 9