Jika m=akar 18 +akar 80,maka nilai (m-7akar 2)(m+7akar 2) =

jawab

m = √18 + √80
m = 3√2 + 4√5

nilai  (m - 7√2)(m + 7√2) =  m² - 98
= (3√2 + 4√5)² - 98
= 18+ 80 + 24√10   - 98
= 98 + 24√10 - 98
= 24 √10