Question 228592
# 1

{{{sqrt(y-5)=5}}} Start with the given equation



{{{y-5=5^2}}} Square both sides.



{{{y-5=25}}} Square 5 to get 25



{{{y=30}}} Add 5 to both sides.



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# 2

{{{9^(3/2)^""=(9^(1/2))^3=(sqrt(9))^3=3^3=27}}}


So {{{9^(3/2)^""=27}}}


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# 3


{{{3*sqrt(-125)=3*sqrt(-1*25*5)=3*sqrt(-1)*sqrt(25)*sqrt(5)=-3i*5*sqrt(5)=-15i*sqrt(5)}}}



So {{{3*sqrt(-125)=-15i*sqrt(5)}}}


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# 4


{{{3*sqrt(375)=3*sqrt(25*15)=3*sqrt(25)*sqrt(15)=3*5*sqrt(15)=15*sqrt(15)}}}



So {{{3*sqrt(375)=15*sqrt(15)}}}