Can some explain this equation ?? z = -4a for a

If 1/√5+1/√5+1=p+q√r , find the values of p, q and r

Select the two pairs of figures that are similar.

Avery’s piggy bank has 300 nickels, 450 pennies, and 150 dimes. she randomly picks three coins. each time she picks a coin, she makes a note of it and puts it back into the piggy bank before picking the next coin.