Simplify (x+ square root of 7)(x- square root of 7)

$(x + \sqrt{7}) (x - \sqrt{7})$

Expand $(x + \sqrt{7}) (x - \sqrt{7})$ using the FOIL Method.

Apply the distributive property.

$x (x - \sqrt{7}) + \sqrt{7} (x - \sqrt{7})$

Apply the distributive property.

$x \cdot x + x (- \sqrt{7}) + \sqrt{7} (x - \sqrt{7})$

Apply the distributive property.

$x \cdot x + x (- \sqrt{7}) + \sqrt{7} x + \sqrt{7} (- \sqrt{7})$

Simplify terms.

Combine the opposite terms in $x \cdot x + x (- \sqrt{7}) + \sqrt{7} x + \sqrt{7} (- \sqrt{7})$ .

Reorder the factors in the terms $x (- \sqrt{7})$ and $\sqrt{7} x$ .

$x \cdot x - x \sqrt{7} + x \sqrt{7} + \sqrt{7} (- \sqrt{7})$

Add $- x \sqrt{7}$ and $x \sqrt{7}$ .

$x \cdot x + 0 + \sqrt{7} (- \sqrt{7})$

Add $x \cdot x$ and $0$ .

$x \cdot x + \sqrt{7} (- \sqrt{7})$

Simplify each term.

Multiply $x$ by $x$ .

$x^{2} + \sqrt{7} (- \sqrt{7})$

Multiply $\sqrt{7} (- \sqrt{7})$ .

Raise $\sqrt{7}$ to the power of $1$ .

$x^{2} - ({\sqrt{7}}^{1} \sqrt{7})$

Raise $\sqrt{7}$ to the power of $1$ .

$x^{2} - ({\sqrt{7}}^{1} {\sqrt{7}}^{1})$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$x^{2} - {\sqrt{7}}^{1 + 1}$

Add $1$ and $1$ .

$x^{2} - {\sqrt{7}}^{2}$

Rewrite ${\sqrt{7}}^{2}$ as $7$ .

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{7}$ as $7^{\frac{1}{2}}$ .

$x^{2} - {(7^{\frac{1}{2}})}^{2}$

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$x^{2} - 7^{\frac{1}{2} \cdot 2}$

Combine $\frac{1}{2}$ and $2$ .

$x^{2} - 7^{\frac{2}{2}}$

Cancel the common factor of $2$ .

Cancel the common factor.

$x^{2} - 7^{\frac{2}{2}}$

Rewrite the expression.

$x^{2} - 7^{1}$

Evaluate the exponent.

$x^{2} - 1 \cdot 7$

Multiply $- 1$ by $7$ .

$x^{2} - 7$