Question

a) (2√3-1) (2√3+1)=
b) 2√18+5√2-√72=
c) √5(1/√5 - 2/√5) =
d) -√8 · ( 2/√2 + 2√2) =

Ajutoor

Answer 1

a ) (2√3-1) (2√3+1)= 12 + 2√3 - 2√3 -1 = 11
b ) 2√18+5√2-√72= 6√2 + 5√2 - 6√2 = 5√2
c ) √5(1/√5 - 2/√5) = √5 ( √5 / 5 - 2√5/5 ) = √5 x ( -√5 / 5  ) = -5/5 = -1
d ) -√8 · ( 2/√2 + 2√2) =  - 2√2 ( 2√2 / 2 + 2√2 ) = 2√2 ( 2√2/2 + 4√2 /2) 
= 2√2 x 3√2 = 12