2x10+3a=59 What is a?​

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.

If i had 1234 apples and 1 banana what is the total amount

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