Please help, brainliest awarded to actual answers

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Which exponential function has an initial value of 2? f(x) = 2(3x) f(x) = 3(2x)

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