What is a value or values that make an equation true

Any value that satisfies the equality.
E.g. 2x + 4x = 10 the value that makes this true is 2

or 

x^2 = 2 The values that would make it true are 4 and -4, since the squared of any number is always a positive.

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 *_*