Answer:
B. -19
Step-by-step explanation:
A second degree polynomial can be factored if the discriminant is greater of equal to zero.
For a polynomial of the type: ax2 + bx + c, the discriminant is given by:
b^2 - 4ac.
In this case, a=1, b=b and c=18. Therefore:
b^2 - 4ac = b^2 - 72.
Option C and D are automatically discarded, given that if b equals 7 or 3 the discriminant will be negative, and the polynomial will have no real roots.
Now, if b equals 17 or -19 the polynomial can be factored. But, if b=17 the solution will be a decimal number. Therefore, the correct answer is B.
Substituting the value of B, we have:
x2 - 19x + 18 = 0
(x-1)(x-18)=0
