Question

I need help with this practice It is trig from my ACT prep guideI will send an additional picture later of my attempted answer of this

Answer 1

Step-by-step explanation

Angle α lies in quadrant II, which means that its sine is positive and its cosine is negative.

Angle β lies in quadrant IV, which means that its cosine is positive and its sine is negative,

The cosine of a difference of two angles is,