Solve for x
x=\sqrt{37}+5\approx 11.08276253
x=5-\sqrt{37}\approx -1.08276253
Graph
Quiz
Quadratic Equation
5 problems similar to:
\frac { 2 x + 3 } { x - 2 } = \frac { 1 } { 4 } \quad x = ?
Share
Copied to clipboard
4\left(2x+3\right)=\frac{1}{4}x\times 4\left(x-2\right)
Variable x cannot be equal to 2 since division by zero is not defined. Multiply both sides of the equation by 4\left(x-2\right), the least common multiple of x-2,4.
8x+12=\frac{1}{4}x\times 4\left(x-2\right)
Use the distributive property to multiply 4 by 2x+3.
8x+12=x\left(x-2\right)
Multiply \frac{1}{4} and 4 to get 1.
8x+12=x^{2}-2x
Use the distributive property to multiply x by x-2.
8x+12-x^{2}=-2x
Subtract x^{2} from both sides.
8x+12-x^{2}+2x=0
Add 2x to both sides.
10x+12-x^{2}=0
Combine 8x and 2x to get 10x.
-x^{2}+10x+12=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{-10±\sqrt{10^{2}-4\left(-1\right)\times 12}}{2\left(-1\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -1 for a, 10 for b, and 12 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-10±\sqrt{100-4\left(-1\right)\times 12}}{2\left(-1\right)}
Square 10.
x=\frac{-10±\sqrt{100+4\times 12}}{2\left(-1\right)}
Multiply -4 times -1.
x=\frac{-10±\sqrt{100+48}}{2\left(-1\right)}
Multiply 4 times 12.
x=\frac{-10±\sqrt{148}}{2\left(-1\right)}
Add 100 to 48.
x=\frac{-10±2\sqrt{37}}{2\left(-1\right)}
Take the square root of 148.
x=\frac{-10±2\sqrt{37}}{-2}
Multiply 2 times -1.
x=\frac{2\sqrt{37}-10}{-2}
Now solve the equation x=\frac{-10±2\sqrt{37}}{-2} when ± is plus. Add -10 to 2\sqrt{37}.
x=5-\sqrt{37}
Divide -10+2\sqrt{37} by -2.
x=\frac{-2\sqrt{37}-10}{-2}
Now solve the equation x=\frac{-10±2\sqrt{37}}{-2} when ± is minus. Subtract 2\sqrt{37} from -10.
x=\sqrt{37}+5
Divide -10-2\sqrt{37} by -2.
x=5-\sqrt{37} x=\sqrt{37}+5
The equation is now solved.
4\left(2x+3\right)=\frac{1}{4}x\times 4\left(x-2\right)
Variable x cannot be equal to 2 since division by zero is not defined. Multiply both sides of the equation by 4\left(x-2\right), the least common multiple of x-2,4.
8x+12=\frac{1}{4}x\times 4\left(x-2\right)
Use the distributive property to multiply 4 by 2x+3.
8x+12=x\left(x-2\right)
Multiply \frac{1}{4} and 4 to get 1.
8x+12=x^{2}-2x
Use the distributive property to multiply x by x-2.
8x+12-x^{2}=-2x
Subtract x^{2} from both sides.
8x+12-x^{2}+2x=0
Add 2x to both sides.
10x+12-x^{2}=0
Combine 8x and 2x to get 10x.
10x-x^{2}=-12
Subtract 12 from both sides. Anything subtracted from zero gives its negation.
-x^{2}+10x=-12
Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.
\frac{-x^{2}+10x}{-1}=-\frac{12}{-1}
Divide both sides by -1.
x^{2}+\frac{10}{-1}x=-\frac{12}{-1}
Dividing by -1 undoes the multiplication by -1.
x^{2}-10x=-\frac{12}{-1}
Divide 10 by -1.
x^{2}-10x=12
Divide -12 by -1.
x^{2}-10x+\left(-5\right)^{2}=12+\left(-5\right)^{2}
Divide -10, the coefficient of the x term, by 2 to get -5. Then add the square of -5 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-10x+25=12+25
Square -5.
x^{2}-10x+25=37
Add 12 to 25.
\left(x-5\right)^{2}=37
Factor x^{2}-10x+25. 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-5\right)^{2}}=\sqrt{37}
Take the square root of both sides of the equation.
x-5=\sqrt{37} x-5=-\sqrt{37}
Simplify.
x=\sqrt{37}+5 x=5-\sqrt{37}
Add 5 to both sides of the equation.
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}