Question

The quadratic equation 2x ² +bx+18=0 has a double root. Find all possible values of b. If you find more than one, then list the values separated by commas.
a) -6
b) 6
c) -9
d) 9

Answer 1

Answer:

Step-by-step explanation:

Take the equation ax^2 + bx + c = 0, it has a double root if b^2 - 4ac = 0.

So we have:

b^2 - 4*2*18 = 0

b^2 = 144

b = +/-12