one last example needed?

Question

√3y+7=5 the solution is y=

Answer 1

if its sqrt(3x)+7=5
sqrt(3x)=-2
3x=(-2)^2=4
x=4/3

if its sqrt(3x+7)=5
3x+7=5^2=25
3x=18
x=6

Answer 2

Please learn to use parentheses. It will eliminate ambiguity.

Did you mean:

√(3y) + 7 = 5
√(3y) = -2

There is no real solution because square roots are not negative.
_____________

Or did you mean:

√(3y + 7) = 5

Square both sides.

3y + 7 = 25
3y = 18
y = 6

Answer 3

sqrt(3y) + 7 = 5

Sqrt (3y) = -2

(sqrt(3y))^2 = (-2)^2

3y = 4

y = +/- 4/3