Question

Can someone please please please help? I'm so confused. I've been on this problem for an hour.

Answer 1

`\cos(A-B)=\cos A\cdot\cos B+\sin A\cdot\sin B=(35)/(37)\cdot(21)/(29)+(12)/(37)\cdot(20)/(29)=\\\\\\=(735)/(1073)+(240)/(1073)=(975)/(1073)\approx0.91`