Select all of the following that are quadratic equations. 5 x 2+ 15 x = 0 6 x - 1 = 4 x + 7 x 2 - 4 x = 4 x + 7 2 x - 1 = 0 3 x 2 + 5 x - 7 = 0 x 3 - 2 x 2 + 1 = 0

i believe your answer is b.

good luck!

cutie~

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 *_*