How to determine # of solutions to sqroot of x+5=x?

  • Thread starter gurpalc
  • Start date
In summary, the equation √x+5=x has one real solution. The attempt at a solution involved squaring both sides and forming a quadratic equation. However, this resulted in an extra solution that does not satisfy the original equation. To find the correct solution, it is necessary to substitute the values back into the original equation or to graph the lines.
  • #1
gurpalc
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Homework Statement



How many real solutions does the equation √x+5=x have?

Homework Equations



n/a

The Attempt at a Solution



I squared both sides so I got x+5=x^2 then I formed a quadratic equation: x^2-x-5=0

I got two real solutions but the answer is one.

I know it has something to do with x+5 being sqrooted but I don't know how to go about solving it.
 
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  • #2
Well you did it correctly, but when you squared it, you picked up an additional answer which satisfies the quadratic formed. But really you want your value to satisfy the original equation. So you will need to sub back in the values to see if you get the same number on the left hand side and right hand side of the equations.

It's like you start off with x= 1 and then get x^2-1=0 = (x+1)(x-1) such that x= 1 or -1.

Alternatively, you could have sketched/graphed the lines.
 

Related to How to determine # of solutions to sqroot of x+5=x?

1. How do you solve "sqroot of x+5=x" to determine the number of solutions?

To determine the number of solutions, we first need to isolate the square root term on one side of the equation. We can do this by subtracting 5 from both sides of the equation. This will leave us with √x = x - 5. Next, we can square both sides of the equation to eliminate the square root. This will give us x = x^2 - 10x + 25. Finally, we can rearrange the equation to get it in standard quadratic form, which is 0 = x^2 - 11x + 25. We can then use the quadratic formula to solve for x and determine the number of solutions.

2. Can this equation have more than one solution?

Yes, this equation can have more than one solution. Depending on the values of x, the quadratic formula may produce two distinct solutions, one solution, or no real solutions.

3. What does it mean if the quadratic formula produces two solutions?

If the quadratic formula produces two solutions, it means that the original equation has two distinct solutions. This means that there are two different values of x that satisfy the equation and make it true.

4. How do you know if the equation has no real solutions?

If the discriminant (b^2 - 4ac) in the quadratic formula is negative, it means that the equation has no real solutions. This is because the square root of a negative number is not a real number. In this case, the solutions to the equation would be complex numbers.

5. Can you use a graph to determine the number of solutions?

Yes, you can use a graph to determine the number of solutions. The number of times the graph of the equation intersects the x-axis is equal to the number of solutions. If the graph intersects the x-axis twice, it means there are two solutions. If the graph intersects the x-axis once, it means there is one solution. And if the graph does not intersect the x-axis at all, it means there are no real solutions to the equation.

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