Solve for x
x=0.5
x=3.5
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Quadratic Equation
5 problems similar to:
( 2 - x ) ^ { 2 } + ( 1.5 + 0.5 ) ^ { 2 } = 2.5 ^ { 2 }
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4-4x+x^{2}+\left(1.5+0.5\right)^{2}=2.5^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(2-x\right)^{2}.
4-4x+x^{2}+2^{2}=2.5^{2}
Add 1.5 and 0.5 to get 2.
4-4x+x^{2}+4=2.5^{2}
Calculate 2 to the power of 2 and get 4.
8-4x+x^{2}=2.5^{2}
Add 4 and 4 to get 8.
8-4x+x^{2}=6.25
Calculate 2.5 to the power of 2 and get 6.25.
8-4x+x^{2}-6.25=0
Subtract 6.25 from both sides.
1.75-4x+x^{2}=0
Subtract 6.25 from 8 to get 1.75.
x^{2}-4x+1.75=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(-4\right)±\sqrt{\left(-4\right)^{2}-4\times 1.75}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -4 for b, and 1.75 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-4\right)±\sqrt{16-4\times 1.75}}{2}
Square -4.
x=\frac{-\left(-4\right)±\sqrt{16-7}}{2}
Multiply -4 times 1.75.
x=\frac{-\left(-4\right)±\sqrt{9}}{2}
Add 16 to -7.
x=\frac{-\left(-4\right)±3}{2}
Take the square root of 9.
x=\frac{4±3}{2}
The opposite of -4 is 4.
x=\frac{7}{2}
Now solve the equation x=\frac{4±3}{2} when ± is plus. Add 4 to 3.
x=\frac{1}{2}
Now solve the equation x=\frac{4±3}{2} when ± is minus. Subtract 3 from 4.
x=\frac{7}{2} x=\frac{1}{2}
The equation is now solved.
4-4x+x^{2}+\left(1.5+0.5\right)^{2}=2.5^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(2-x\right)^{2}.
4-4x+x^{2}+2^{2}=2.5^{2}
Add 1.5 and 0.5 to get 2.
4-4x+x^{2}+4=2.5^{2}
Calculate 2 to the power of 2 and get 4.
8-4x+x^{2}=2.5^{2}
Add 4 and 4 to get 8.
8-4x+x^{2}=6.25
Calculate 2.5 to the power of 2 and get 6.25.
-4x+x^{2}=6.25-8
Subtract 8 from both sides.
-4x+x^{2}=-1.75
Subtract 8 from 6.25 to get -1.75.
x^{2}-4x=-1.75
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.
x^{2}-4x+\left(-2\right)^{2}=-1.75+\left(-2\right)^{2}
Divide -4, the coefficient of the x term, by 2 to get -2. Then add the square of -2 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}-4x+4=-1.75+4
Square -2.
x^{2}-4x+4=2.25
Add -1.75 to 4.
\left(x-2\right)^{2}=2.25
Factor x^{2}-4x+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-2\right)^{2}}=\sqrt{2.25}
Take the square root of both sides of the equation.
x-2=\frac{3}{2} x-2=-\frac{3}{2}
Simplify.
x=\frac{7}{2} x=\frac{1}{2}
Add 2 to both sides of the equation.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
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Linear equation
y = 3x + 4
Arithmetic
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Matrix
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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}