1. Which of the following is not an arithmetic sequence? a. 11, 2, -8, -19
b. 4, 7, 10, 13
C. 57, 51, 45, 39...
d. -3, -5, -7, -9

Answer to your question: a. the fundamental theorem of algebra tells you that the equation will have two complex roots since the degree of the polynomial is 2. the roots are ​ x=1±i7√2 .number of roots=degree of polynomialhere, degree of polynomial is 2 so number of roots will be 2.hope it *_*