Answer: 28 is correct!!
Step-by-step explanation:
The discriminant is b^2-4ac
ax^2+bx+c=0
x^2+11x-10=0
11^2-4(1)(-10)
1. Simplify 11^2 to 121
121-4(1)(-10)
2. Simplify 4*1*-10 to -40
121-(-40)
3. Simplify brackets
121+40
4. Simplify
161
Your discriminant is 161
A and C both work.
Just be sure to watch the multiplying by the negatives to be sure of your answers.