Evaluate
7.8
Factor
\frac{3 \cdot 13}{5} = 7\frac{4}{5} = 7.8
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\frac{3.9}{2}\times 4
Multiply 2.6 and 1.5 to get 3.9.
\frac{39}{20}\times 4
Expand \frac{3.9}{2} by multiplying both numerator and the denominator by 10.
\frac{39\times 4}{20}
Express \frac{39}{20}\times 4 as a single fraction.
\frac{156}{20}
Multiply 39 and 4 to get 156.
\frac{39}{5}
Reduce the fraction \frac{156}{20} to lowest terms by extracting and canceling out 4.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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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}