5аb/a+5b *(a/5b-5b/a) при а= 5√7+9,b=√7-9

Question

5аb/a+5b *(a/5b-5b/a) при а= 5√7+9,b=√7-9

Answer 1

5*(s7-9)+ 5s7 - 25(s7-9)^2 =-9 - 25*(7-18s7+81) = - 2209 + 450*sqrt(7)