Factor
\left(x-2\right)\left(x+7\right)
Evaluate
\left(x-2\right)\left(x+7\right)
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a+b=5 ab=1\left(-14\right)=-14
Factor the expression by grouping. First, the expression needs to be rewritten as x^{2}+ax+bx-14. To find a and b, set up a system to be solved.
-1,14 -2,7
Since ab is negative, a and b have the opposite signs. Since a+b is positive, the positive number has greater absolute value than the negative. List all such integer pairs that give product -14.
-1+14=13 -2+7=5
Calculate the sum for each pair.
a=-2 b=7
The solution is the pair that gives sum 5.
\left(x^{2}-2x\right)+\left(7x-14\right)
Rewrite x^{2}+5x-14 as \left(x^{2}-2x\right)+\left(7x-14\right).
x\left(x-2\right)+7\left(x-2\right)
Factor out x in the first and 7 in the second group.
\left(x-2\right)\left(x+7\right)
Factor out common term x-2 by using distributive property.
x^{2}+5x-14=0
Quadratic polynomial can be factored using the transformation ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right), where x_{1} and x_{2} are the solutions of the quadratic equation ax^{2}+bx+c=0.
x=\frac{-5±\sqrt{5^{2}-4\left(-14\right)}}{2}
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
x=\frac{-5±\sqrt{25-4\left(-14\right)}}{2}
Square 5.
x=\frac{-5±\sqrt{25+56}}{2}
Multiply -4 times -14.
x=\frac{-5±\sqrt{81}}{2}
Add 25 to 56.
x=\frac{-5±9}{2}
Take the square root of 81.
x=\frac{4}{2}
Now solve the equation x=\frac{-5±9}{2} when ± is plus. Add -5 to 9.
x=2
Divide 4 by 2.
x=-\frac{14}{2}
Now solve the equation x=\frac{-5±9}{2} when ± is minus. Subtract 9 from -5.
x=-7
Divide -14 by 2.
x^{2}+5x-14=\left(x-2\right)\left(x-\left(-7\right)\right)
Factor the original expression using ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right). Substitute 2 for x_{1} and -7 for x_{2}.
x^{2}+5x-14=\left(x-2\right)\left(x+7\right)
Simplify all the expressions of the form p-\left(-q\right) to p+q.
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}