If the discriminate is equal to -2, how many solutions are there

Haley buys 9 pounds of apples for $3. how many pounds of apples can she buy for $1?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

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