1−2√52+3√2=(1−2√52+3√2)(2−3√22−3√2)
= 2−3√2−4√5+6√104−6√2+6√2−18
= 2−3√2−4√5+6√10−14
= 114(3√2+4√5−2−6√10) (dividing through with the minus sign)