Evaluate
\left(2x-1\right)\left(2x+5\right)
Expand
4x^{2}+8x-5
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8x^{2}+4x-4-\left(2x-1\right)^{2}
Use the distributive property to multiply x+1 by 8x-4 and combine like terms.
8x^{2}+4x-4-\left(4x^{2}-4x+1\right)
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(2x-1\right)^{2}.
8x^{2}+4x-4-4x^{2}+4x-1
To find the opposite of 4x^{2}-4x+1, find the opposite of each term.
4x^{2}+4x-4+4x-1
Combine 8x^{2} and -4x^{2} to get 4x^{2}.
4x^{2}+8x-4-1
Combine 4x and 4x to get 8x.
4x^{2}+8x-5
Subtract 1 from -4 to get -5.
8x^{2}+4x-4-\left(2x-1\right)^{2}
Use the distributive property to multiply x+1 by 8x-4 and combine like terms.
8x^{2}+4x-4-\left(4x^{2}-4x+1\right)
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(2x-1\right)^{2}.
8x^{2}+4x-4-4x^{2}+4x-1
To find the opposite of 4x^{2}-4x+1, find the opposite of each term.
4x^{2}+4x-4+4x-1
Combine 8x^{2} and -4x^{2} to get 4x^{2}.
4x^{2}+8x-4-1
Combine 4x and 4x to get 8x.
4x^{2}+8x-5
Subtract 1 from -4 to get -5.
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}