( 2 x - 1 ) ( 5 + x ) = ( 0,5 x + 4 ) ( x - 3 )
Solve for x
x=-\frac{7}{3}\approx -2,333333333
x=-2
Graph
Share
Copied to clipboard
9x+2x^{2}-5=\left(0,5x+4\right)\left(x-3\right)
Use the distributive property to multiply 2x-1 by 5+x and combine like terms.
9x+2x^{2}-5=0,5x^{2}+2,5x-12
Use the distributive property to multiply 0,5x+4 by x-3 and combine like terms.
9x+2x^{2}-5-0,5x^{2}=2,5x-12
Subtract 0,5x^{2} from both sides.
9x+1,5x^{2}-5=2,5x-12
Combine 2x^{2} and -0,5x^{2} to get 1,5x^{2}.
9x+1,5x^{2}-5-2,5x=-12
Subtract 2,5x from both sides.
6,5x+1,5x^{2}-5=-12
Combine 9x and -2,5x to get 6,5x.
6,5x+1,5x^{2}-5+12=0
Add 12 to both sides.
6,5x+1,5x^{2}+7=0
Add -5 and 12 to get 7.
1,5x^{2}+6,5x+7=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{-6,5±\sqrt{6,5^{2}-4\times 1,5\times 7}}{2\times 1,5}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1,5 for a, 6,5 for b, and 7 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-6,5±\sqrt{42,25-4\times 1,5\times 7}}{2\times 1,5}
Square 6,5 by squaring both the numerator and the denominator of the fraction.
x=\frac{-6,5±\sqrt{42,25-6\times 7}}{2\times 1,5}
Multiply -4 times 1,5.
x=\frac{-6,5±\sqrt{42,25-42}}{2\times 1,5}
Multiply -6 times 7.
x=\frac{-6,5±\sqrt{0,25}}{2\times 1,5}
Add 42,25 to -42.
x=\frac{-6,5±\frac{1}{2}}{2\times 1,5}
Take the square root of 0,25.
x=\frac{-6,5±\frac{1}{2}}{3}
Multiply 2 times 1,5.
x=-\frac{6}{3}
Now solve the equation x=\frac{-6,5±\frac{1}{2}}{3} when ± is plus. Add -6,5 to \frac{1}{2} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
x=-2
Divide -6 by 3.
x=-\frac{7}{3}
Now solve the equation x=\frac{-6,5±\frac{1}{2}}{3} when ± is minus. Subtract \frac{1}{2} from -6,5 by finding a common denominator and subtracting the numerators. Then reduce the fraction to lowest terms if possible.
x=-2 x=-\frac{7}{3}
The equation is now solved.
9x+2x^{2}-5=\left(0,5x+4\right)\left(x-3\right)
Use the distributive property to multiply 2x-1 by 5+x and combine like terms.
9x+2x^{2}-5=0,5x^{2}+2,5x-12
Use the distributive property to multiply 0,5x+4 by x-3 and combine like terms.
9x+2x^{2}-5-0,5x^{2}=2,5x-12
Subtract 0,5x^{2} from both sides.
9x+1,5x^{2}-5=2,5x-12
Combine 2x^{2} and -0,5x^{2} to get 1,5x^{2}.
9x+1,5x^{2}-5-2,5x=-12
Subtract 2,5x from both sides.
6,5x+1,5x^{2}-5=-12
Combine 9x and -2,5x to get 6,5x.
6,5x+1,5x^{2}=-12+5
Add 5 to both sides.
6,5x+1,5x^{2}=-7
Add -12 and 5 to get -7.
1,5x^{2}+6,5x=-7
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{1,5x^{2}+6,5x}{1,5}=-\frac{7}{1,5}
Divide both sides of the equation by 1,5, which is the same as multiplying both sides by the reciprocal of the fraction.
x^{2}+\frac{6,5}{1,5}x=-\frac{7}{1,5}
Dividing by 1,5 undoes the multiplication by 1,5.
x^{2}+\frac{13}{3}x=-\frac{7}{1,5}
Divide 6,5 by 1,5 by multiplying 6,5 by the reciprocal of 1,5.
x^{2}+\frac{13}{3}x=-\frac{14}{3}
Divide -7 by 1,5 by multiplying -7 by the reciprocal of 1,5.
x^{2}+\frac{13}{3}x+\frac{13}{6}^{2}=-\frac{14}{3}+\frac{13}{6}^{2}
Divide \frac{13}{3}, the coefficient of the x term, by 2 to get \frac{13}{6}. Then add the square of \frac{13}{6} to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+\frac{13}{3}x+\frac{169}{36}=-\frac{14}{3}+\frac{169}{36}
Square \frac{13}{6} by squaring both the numerator and the denominator of the fraction.
x^{2}+\frac{13}{3}x+\frac{169}{36}=\frac{1}{36}
Add -\frac{14}{3} to \frac{169}{36} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.
\left(x+\frac{13}{6}\right)^{2}=\frac{1}{36}
Factor x^{2}+\frac{13}{3}x+\frac{169}{36}. 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{13}{6}\right)^{2}}=\sqrt{\frac{1}{36}}
Take the square root of both sides of the equation.
x+\frac{13}{6}=\frac{1}{6} x+\frac{13}{6}=-\frac{1}{6}
Simplify.
x=-2 x=-\frac{7}{3}
Subtract \frac{13}{6} from 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}