a) Fill in the blanks with positive integers:
\((3+√5)^3\) = __+ __\(√5 \)
b) Find the coefficient of \(y^4 \) 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