SOLUTION: i am having trouble with how to solve for the unknown in this sqrt of y +(sqrt of y+7)= 7 please help me if possible

Click here to see ALL problems on Systems-of-equations

Question 277505: i am having trouble with how to solve for the unknown in this sqrt of y +(sqrt of y+7)= 7 please help me if possible
Found 2 solutions by dabanfield, stanbon:
Answer by dabanfield(803) (Show Source):
You can put this solution on YOUR website!
If sqrt(y+7) = 7
then squairing both sides we have:
y+7 = 49
y = 49-7
y = 42

Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
sqrt of y +(sqrt of y+7)= 7
-------------------------
sqrt(y)+sqrt(y+7) = 7
---
Square both sides to get:
y + 2sqrt(y^2+7y) + y+7 = 49
---
2sqrt(y^2+7y) = 42-2y
---
sqrt(y^2+7y) = 21-y
---
Square both sides:
y^2+7y = 441 - 42y + y^2
49y = 441
y = 9
------
Check in the original equation:
sqrt(9)+sqrt(16) = 7
3 + 4 = 7
-------
Solution: y = 9
============================
cheers,
Stan H.