What is the value of a from x2 + 2x + 3 = 0

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b

How do you do the foil method with polynomials?

2,10,-50 next two numbers geometric sequence