I don't get how this expression simplifies to this answer. I'm supposed to distribute the 5, but I have no idea where that +5 in answer comes from.

I dont get how this expression simplifies to this answer Im supposed to distribute the 5 but I have no idea where that 5 in answer comes from class=

Respuesta :

[tex]\frac{5}{3-\sqrt[]{7}}[/tex]

To simplify this fraction multiply up and down by the conjugate of the denominator

The conjugate to the denominator has the same terms but different middle sign

Then the conjugate of

[tex]3-\sqrt[]{7}\text{ is 3+}\sqrt[]{7}[/tex]

So multiply up and down by 3 + root 7

[tex]\frac{5}{3-\sqrt[]{7}}\times\frac{3+\sqrt[]{7}}{3+\sqrt[]{7}}[/tex]

Let us multiply the two denominators

[tex](3-\sqrt[]{7})(3+\sqrt[]{7})=(3)^2-(\sqrt[]{7})^2=9-7=2[/tex]

Now let us multiply the 2 numerators

[tex]5\times(3+\sqrt[]{7})=5(3)+5(\sqrt[]{7})=15+5\sqrt[]{7}[/tex]

The simplest form of the fraction is

[tex]\frac{15+5\sqrt[]{7}}{2}[/tex]