1.(7+4√3)(2-√3)^2 2.√(1又25分之1)^2-(2/5)^2 3.√80*√5-√50*√2 4.√4/3÷√3/2*√9/8

1.(7+4√3)(2-√3)^2 2.√(1又25分之1)^2-(2/5)^2 3.√80*√5-√50*√2 4.√4/3÷√3/2*√9/8

1.(7+4√3)(2-√3)^2
=(7+4√3)(4-4√3+3)
=(7+4√3)(7-4√3)
=49-48
=1
2.√(1又25分之1)^2-(2/5)^2
=√(26/25+2/5)(26/25-2/5)
=√36/25x24/25
=12/5√6
3.√80*√5-√50*√2
=√400-√100
=20-10
=10
4.√4/3÷√3/2*√9/8 9不明白