Question

The quadratic equation 2x^2 + bx + 18 = 0 has a double root. Find all possible values of b. Please help!! Giving Brainliest!!

Answer 1

Answer:

b=12 or b=-12

Step-by-step explanation:

If the quadratic equation $2x^2+bx+18=0$ has a double root, then its discriminant is equal to zero. Find the discriminant:

$D=b^2-4\cdot 2\cdot 18=b^2-144.$

Now equate the discriminant to 0:

$b^2-144=0,\\ \\b^2=144,\\ \\b=\pm 12.$