SOLUTION: Solve algebraically and check your potential solutions: sqrt(x+20)-x=0

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Question 98145: Solve algebraically and check your potential solutions: sqrt(x+20)-x=0

Found 2 solutions by mathslover, edjones:
Answer by mathslover(157) About Me  (Show Source):
You can put this solution on YOUR website!
+sqrt%28x%2B20%29+-x=0
+sqrt%28x%2B20%29=x
Square on both sides
+x%2B20+=+x%5E2+
x%5E2+-x+-20+=0
%28x-5%29%28x%2B4%29=0
x=5 and x= -4
Checking by putting x=5
sqrt%285%2B20%29+=+5+
sqrt%2825%29+=5
5=5 x=5 is a solution
Checking by putting x=-4
sqrt%28-4%2B20%29+=+-4
sqrt%2816%29=-4
which is true if we consider the negative root of 16 ie -4
Solution x=5 and x=-4

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
sqrt(x+20)-x=0
sqrt(x+20)=x
square each side: x+20=x^2
x^2-x-20=0
Factor. (x-5)(x+4)=0
x=5 and x=-4
Check:
sqrt(5+20)-5=0 true
sqrt(-4+20)-4=0 true
Ed