Graph f(x) = square root of x-7

$f (x) = \sqrt{x - 7}$

Step 1

Find the domain for $y = \sqrt{x - 7}$ so that a list of $x$ values can be picked to find a list of points, which will help graphing the radical.

Set the radicand in $\sqrt{x - 7}$ greater than or equal to $0$ to find where the expression is defined.

$x - 7 \geq 0$

Add $7$ to both sides of the inequality.

$x \geq 7$

The domain is all values of $x$ that make the expression defined.

Interval Notation:

$[7, \infty)$

Set-Builder Notation:

${x | x \geq 7}$

Interval Notation:

$[7, \infty)$

Set-Builder Notation:

${x | x \geq 7}$

Step 2

To find the radical expression end point, substitute the $x$ value $7$ , which is the least value in the domain, into $f (x) = \sqrt{x - 7}$ .

Replace the variable $x$ with $7$ in the expression.

$f (7) = \sqrt{(7) - 7}$

Simplify the result.

Subtract $7$ from $7$ .

$f (7) = \sqrt{0}$

Rewrite $0$ as $0^{2}$ .

$f (7) = \sqrt{0^{2}}$

Pull terms out from under the radical, assuming positive real numbers.

$f (7) = 0$

The final answer is $0$ .

$0$

Step 3

The radical expression end point is $(7, 0)$ .

$(7, 0)$

Step 4

Select a few $x$ values from the domain. It would be more useful to select the values so that they are next to the $x$ value of the radical expression end point.

Substitute the $x$ value $8$ into $f (x) = \sqrt{x - 7}$ . In this case, the point is $(8, 1)$ .

Replace the variable $x$ with $8$ in the expression.

$f (8) = \sqrt{(8) - 7}$

Simplify the result.

Subtract $7$ from $8$ .

$f (8) = \sqrt{1}$

Any root of $1$ is $1$ .

$f (8) = 1$

The final answer is $1$ .

$y = 1$

Substitute the $x$ value $9$ into $f (x) = \sqrt{x - 7}$ . In this case, the point is $(9, \sqrt{2})$ .

Replace the variable $x$ with $9$ in the expression.

$f (9) = \sqrt{(9) - 7}$

Simplify the result.

Subtract $7$ from $9$ .

$f (9) = \sqrt{2}$

The final answer is $\sqrt{2}$ .

$y = \sqrt{2}$

The square root can be graphed using the points around the vertex $(7, 0), (8, 1), (9, 1.41)$

$\begin{array}{c} x & y \\ 7 & 0 \\ 8 & 1 \\ 9 & 1.41 \end{array}$

Step 5

Graph f(x) = square root of x-7

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