Skip to main content
Solve for x
Tick mark Image
Graph

Similar Problems from Web Search

Share

1-5x-\left(4x+1\right)x=\left(x-2\right)\times 2
Variable x cannot be equal to any of the values -\frac{1}{4},2 since division by zero is not defined. Multiply both sides of the equation by \left(x-2\right)\left(4x+1\right), the least common multiple of 4x^{2}-7x-2,x-2,4x+1.
1-5x-\left(4x^{2}+x\right)=\left(x-2\right)\times 2
Use the distributive property to multiply 4x+1 by x.
1-5x-4x^{2}-x=\left(x-2\right)\times 2
To find the opposite of 4x^{2}+x, find the opposite of each term.
1-6x-4x^{2}=\left(x-2\right)\times 2
Combine -5x and -x to get -6x.
1-6x-4x^{2}=2x-4
Use the distributive property to multiply x-2 by 2.
1-6x-4x^{2}-2x=-4
Subtract 2x from both sides.
1-8x-4x^{2}=-4
Combine -6x and -2x to get -8x.
1-8x-4x^{2}+4=0
Add 4 to both sides.
5-8x-4x^{2}=0
Add 1 and 4 to get 5.
-4x^{2}-8x+5=0
Rearrange the polynomial to put it in standard form. Place the terms in order from highest to lowest power.
a+b=-8 ab=-4\times 5=-20
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as -4x^{2}+ax+bx+5. To find a and b, set up a system to be solved.
1,-20 2,-10 4,-5
Since ab is negative, a and b have the opposite signs. Since a+b is negative, the negative number has greater absolute value than the positive. List all such integer pairs that give product -20.
1-20=-19 2-10=-8 4-5=-1
Calculate the sum for each pair.
a=2 b=-10
The solution is the pair that gives sum -8.
\left(-4x^{2}+2x\right)+\left(-10x+5\right)
Rewrite -4x^{2}-8x+5 as \left(-4x^{2}+2x\right)+\left(-10x+5\right).
2x\left(-2x+1\right)+5\left(-2x+1\right)
Factor out 2x in the first and 5 in the second group.
\left(-2x+1\right)\left(2x+5\right)
Factor out common term -2x+1 by using distributive property.
x=\frac{1}{2} x=-\frac{5}{2}
To find equation solutions, solve -2x+1=0 and 2x+5=0.
1-5x-\left(4x+1\right)x=\left(x-2\right)\times 2
Variable x cannot be equal to any of the values -\frac{1}{4},2 since division by zero is not defined. Multiply both sides of the equation by \left(x-2\right)\left(4x+1\right), the least common multiple of 4x^{2}-7x-2,x-2,4x+1.
1-5x-\left(4x^{2}+x\right)=\left(x-2\right)\times 2
Use the distributive property to multiply 4x+1 by x.
1-5x-4x^{2}-x=\left(x-2\right)\times 2
To find the opposite of 4x^{2}+x, find the opposite of each term.
1-6x-4x^{2}=\left(x-2\right)\times 2
Combine -5x and -x to get -6x.
1-6x-4x^{2}=2x-4
Use the distributive property to multiply x-2 by 2.
1-6x-4x^{2}-2x=-4
Subtract 2x from both sides.
1-8x-4x^{2}=-4
Combine -6x and -2x to get -8x.
1-8x-4x^{2}+4=0
Add 4 to both sides.
5-8x-4x^{2}=0
Add 1 and 4 to get 5.
-4x^{2}-8x+5=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(-8\right)±\sqrt{\left(-8\right)^{2}-4\left(-4\right)\times 5}}{2\left(-4\right)}
This equation is in standard form: ax^{2}+bx+c=0. Substitute -4 for a, -8 for b, and 5 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-8\right)±\sqrt{64-4\left(-4\right)\times 5}}{2\left(-4\right)}
Square -8.
x=\frac{-\left(-8\right)±\sqrt{64+16\times 5}}{2\left(-4\right)}
Multiply -4 times -4.
x=\frac{-\left(-8\right)±\sqrt{64+80}}{2\left(-4\right)}
Multiply 16 times 5.
x=\frac{-\left(-8\right)±\sqrt{144}}{2\left(-4\right)}
Add 64 to 80.
x=\frac{-\left(-8\right)±12}{2\left(-4\right)}
Take the square root of 144.
x=\frac{8±12}{2\left(-4\right)}
The opposite of -8 is 8.
x=\frac{8±12}{-8}
Multiply 2 times -4.
x=\frac{20}{-8}
Now solve the equation x=\frac{8±12}{-8} when ± is plus. Add 8 to 12.
x=-\frac{5}{2}
Reduce the fraction \frac{20}{-8} to lowest terms by extracting and canceling out 4.
x=-\frac{4}{-8}
Now solve the equation x=\frac{8±12}{-8} when ± is minus. Subtract 12 from 8.
x=\frac{1}{2}
Reduce the fraction \frac{-4}{-8} to lowest terms by extracting and canceling out 4.
x=-\frac{5}{2} x=\frac{1}{2}
The equation is now solved.
1-5x-\left(4x+1\right)x=\left(x-2\right)\times 2
Variable x cannot be equal to any of the values -\frac{1}{4},2 since division by zero is not defined. Multiply both sides of the equation by \left(x-2\right)\left(4x+1\right), the least common multiple of 4x^{2}-7x-2,x-2,4x+1.
1-5x-\left(4x^{2}+x\right)=\left(x-2\right)\times 2
Use the distributive property to multiply 4x+1 by x.
1-5x-4x^{2}-x=\left(x-2\right)\times 2
To find the opposite of 4x^{2}+x, find the opposite of each term.
1-6x-4x^{2}=\left(x-2\right)\times 2
Combine -5x and -x to get -6x.
1-6x-4x^{2}=2x-4
Use the distributive property to multiply x-2 by 2.
1-6x-4x^{2}-2x=-4
Subtract 2x from both sides.
1-8x-4x^{2}=-4
Combine -6x and -2x to get -8x.
-8x-4x^{2}=-4-1
Subtract 1 from both sides.
-8x-4x^{2}=-5
Subtract 1 from -4 to get -5.
-4x^{2}-8x=-5
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{-4x^{2}-8x}{-4}=-\frac{5}{-4}
Divide both sides by -4.
x^{2}+\left(-\frac{8}{-4}\right)x=-\frac{5}{-4}
Dividing by -4 undoes the multiplication by -4.
x^{2}+2x=-\frac{5}{-4}
Divide -8 by -4.
x^{2}+2x=\frac{5}{4}
Divide -5 by -4.
x^{2}+2x+1^{2}=\frac{5}{4}+1^{2}
Divide 2, the coefficient of the x term, by 2 to get 1. Then add the square of 1 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+2x+1=\frac{5}{4}+1
Square 1.
x^{2}+2x+1=\frac{9}{4}
Add \frac{5}{4} to 1.
\left(x+1\right)^{2}=\frac{9}{4}
Factor x^{2}+2x+1. 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+1\right)^{2}}=\sqrt{\frac{9}{4}}
Take the square root of both sides of the equation.
x+1=\frac{3}{2} x+1=-\frac{3}{2}
Simplify.
x=\frac{1}{2} x=-\frac{5}{2}
Subtract 1 from both sides of the equation.