a) Fill in the blanks with positive integers:
(3+√5)3 = __+ __√5
b) Find the coefficient of y4 in the expansion of (2y−5)6
b: (ax+b)^6 has a x^4 coefficient of 15*a^4*b^2, so in this case a = 2, b = -5, so 15*16*25 = 3*8*2*125 = 6000
+660 
+57 
