Evaluate
\frac{5\left(\sqrt{7}+2\right)}{3}\approx 7.742918852
Share
Copied to clipboard
\frac{5\left(\sqrt{7}+2\right)}{\left(\sqrt{7}-2\right)\left(\sqrt{7}+2\right)}
Rationalize the denominator of \frac{5}{\sqrt{7}-2} by multiplying numerator and denominator by \sqrt{7}+2.
\frac{5\left(\sqrt{7}+2\right)}{\left(\sqrt{7}\right)^{2}-2^{2}}
Consider \left(\sqrt{7}-2\right)\left(\sqrt{7}+2\right). Multiplication can be transformed into difference of squares using the rule: \left(a-b\right)\left(a+b\right)=a^{2}-b^{2}.
\frac{5\left(\sqrt{7}+2\right)}{7-4}
Square \sqrt{7}. Square 2.
\frac{5\left(\sqrt{7}+2\right)}{3}
Subtract 4 from 7 to get 3.
\frac{5\sqrt{7}+10}{3}
Use the distributive property to multiply 5 by \sqrt{7}+2.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}