SOLUTION: Solve for y, where y is a real number. {{{ sqrt (y + 20 = y) }}} If there is more than one solution, separate them with commas

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Solve for y, where y is a real number. {{{ sqrt (y + 20 = y) }}} If there is more than one solution, separate them with commas      Log On


   

Question 392420: Solve for y, where y is a real number.
+sqrt+%28y+%2B+20+=+y%29+
If there is more than one solution, separate them with commas
Found 2 solutions by nerdybill, robertb:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
I think you mean:
+sqrt+%28y+%2B+20%29+=+y+
square both sides to give you:
+y+%2B+20+=+y%5E2+
+20+=+y%5E2+-+y+
+0+=+y%5E2+-+y+-+20+
+0+=+%28y-5%29%28y%2B4%29+
y = {-4, 5}

Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
sqrt%28y%2B20%29+=+y
Square both sides:
y+%2B+20+=+y%5E2,
==> 0+=+y%5E2+-+y+-+20
==> (y-5)(y+4) = 0 ==> y = 5, -4.
Y = 5 satisfies the original equation, while y = -4 does not.
Therefore the final answer is only y = 5.