Solve for x
x=5
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x^{2}+20=x\left(14-x\right)
Variable x cannot be equal to any of the values 0,2 since division by zero is not defined. Multiply both sides of the equation by x\left(x-2\right), the least common multiple of x\left(x-2\right),x-2.
x^{2}+20=14x-x^{2}
Use the distributive property to multiply x by 14-x.
x^{2}+20-14x=-x^{2}
Subtract 14x from both sides.
x^{2}+20-14x+x^{2}=0
Add x^{2} to both sides.
2x^{2}+20-14x=0
Combine x^{2} and x^{2} to get 2x^{2}.
x^{2}+10-7x=0
Divide both sides by 2.
x^{2}-7x+10=0
Rearrange the polynomial to put it in standard form. Place the terms in order from highest to lowest power.
a+b=-7 ab=1\times 10=10
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as x^{2}+ax+bx+10. To find a and b, set up a system to be solved.
-1,-10 -2,-5
Since ab is positive, a and b have the same sign. Since a+b is negative, a and b are both negative. List all such integer pairs that give product 10.
-1-10=-11 -2-5=-7
Calculate the sum for each pair.
a=-5 b=-2
The solution is the pair that gives sum -7.
\left(x^{2}-5x\right)+\left(-2x+10\right)
Rewrite x^{2}-7x+10 as \left(x^{2}-5x\right)+\left(-2x+10\right).
x\left(x-5\right)-2\left(x-5\right)
Factor out x in the first and -2 in the second group.
\left(x-5\right)\left(x-2\right)
Factor out common term x-5 by using distributive property.
x=5 x=2
To find equation solutions, solve x-5=0 and x-2=0.
x=5
Variable x cannot be equal to 2.
x^{2}+20=x\left(14-x\right)
Variable x cannot be equal to any of the values 0,2 since division by zero is not defined. Multiply both sides of the equation by x\left(x-2\right), the least common multiple of x\left(x-2\right),x-2.
x^{2}+20=14x-x^{2}
Use the distributive property to multiply x by 14-x.
x^{2}+20-14x=-x^{2}
Subtract 14x from both sides.
x^{2}+20-14x+x^{2}=0
Add x^{2} to both sides.
2x^{2}+20-14x=0
Combine x^{2} and x^{2} to get 2x^{2}.
2x^{2}-14x+20=0
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{-\left(-14\right)±\sqrt{\left(-14\right)^{2}-4\times 2\times 20}}{2\times 2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, -14 for b, and 20 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-14\right)±\sqrt{196-4\times 2\times 20}}{2\times 2}
Square -14.
x=\frac{-\left(-14\right)±\sqrt{196-8\times 20}}{2\times 2}
Multiply -4 times 2.
x=\frac{-\left(-14\right)±\sqrt{196-160}}{2\times 2}
Multiply -8 times 20.
x=\frac{-\left(-14\right)±\sqrt{36}}{2\times 2}
Add 196 to -160.
x=\frac{-\left(-14\right)±6}{2\times 2}
Take the square root of 36.
x=\frac{14±6}{2\times 2}
The opposite of -14 is 14.
x=\frac{14±6}{4}
Multiply 2 times 2.
x=\frac{20}{4}
Now solve the equation x=\frac{14±6}{4} when ± is plus. Add 14 to 6.
x=5
Divide 20 by 4.
x=\frac{8}{4}
Now solve the equation x=\frac{14±6}{4} when ± is minus. Subtract 6 from 14.
x=2
Divide 8 by 4.
x=5 x=2
The equation is now solved.
x=5
Variable x cannot be equal to 2.
x^{2}+20=x\left(14-x\right)
Variable x cannot be equal to any of the values 0,2 since division by zero is not defined. Multiply both sides of the equation by x\left(x-2\right), the least common multiple of x\left(x-2\right),x-2.
x^{2}+20=14x-x^{2}
Use the distributive property to multiply x by 14-x.
x^{2}+20-14x=-x^{2}
Subtract 14x from both sides.
x^{2}+20-14x+x^{2}=0
Add x^{2} to both sides.
2x^{2}+20-14x=0
Combine x^{2} and x^{2} to get 2x^{2}.
2x^{2}-14x=-20
Subtract 20 from both sides. Anything subtracted from zero gives its negation.
\frac{2x^{2}-14x}{2}=-\frac{20}{2}
Divide both sides by 2.
x^{2}+\left(-\frac{14}{2}\right)x=-\frac{20}{2}
Dividing by 2 undoes the multiplication by 2.
x^{2}-7x=-\frac{20}{2}
Divide -14 by 2.
x^{2}-7x=-10
Divide -20 by 2.
x^{2}-7x+\left(-\frac{7}{2}\right)^{2}=-10+\left(-\frac{7}{2}\right)^{2}
Divide -7, the coefficient of the x term, by 2 to get -\frac{7}{2}. Then add the square of -\frac{7}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-7x+\frac{49}{4}=-10+\frac{49}{4}
Square -\frac{7}{2} by squaring both the numerator and the denominator of the fraction.
x^{2}-7x+\frac{49}{4}=\frac{9}{4}
Add -10 to \frac{49}{4}.
\left(x-\frac{7}{2}\right)^{2}=\frac{9}{4}
Factor x^{2}-7x+\frac{49}{4}. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(x-\frac{7}{2}\right)^{2}}=\sqrt{\frac{9}{4}}
Take the square root of both sides of the equation.
x-\frac{7}{2}=\frac{3}{2} x-\frac{7}{2}=-\frac{3}{2}
Simplify.
x=5 x=2
Add \frac{7}{2} to both sides of the equation.
x=5
Variable x cannot be equal to 2.
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