#1
2√2+√50-√18=2√2+√25*√2-√9*√2=
2√2+5√2-3√2=4√2
√9m-6√m+√25m=√9*√m-6√m+√25*√m=3√m-6√m+5√m=√m(3-6+5)=2√m
(3√5-√20)√5=3√5*√5-√20*√5=3√5-√10
(√x-√y)(√x-√y)+y=(√x-√y)²+y=x-2√xy+y+y=x-2√xy+2y
(√5+√3)²-2√15=5+2√15+3-2√15=8
#2
1/2√60 и 10√1/5
√1/4*√60 и √100*√1/5
√15<√20<br>#3
6/√12=(6√12)/(√12)²=6√12/12=√12/2
#4
y=x-2
y=√x
x-2=√x
x-√x=2
(√x)²-√x=2
√x(√x-1)=2
x=4
y=4-2
y=2
(4;2)
#5
1/(2√3+1)-1/(2√3-1)=(2√3-1)/(2√3+1)(2√3-1)-(2√3+1)/(2√3-1)(2√3+1)=
(2√3-1)/(2√3)²-1)-(2√3+1)/(2√3)²-1)=
(2√3-1)/11-(2√3+1)/11=(2√3-1-2√3-1)/11=
-2/11