(2√5-√3)(√3+3√5) =
2√5*√3+2√5*3√5-√3*√3-√3*3√5 =
2√15+6√25-√9-3√15 =
2√15-3√15+6*5-3 =
-√15+30-3 =
27-√15
............................
(-2+k)^3 = (k-2)^3
(a – b)^3 = a^3 – 3a^2*b + 3ab^2 – b^3.
(k-2)^3=k^3 - 3*k^2*2+3*2*b^2-2^3 = k^3-6*k^2+6b^2-8
46,73x+53.27=268.05
100x=268.05
x=268.05/100=2.6805