Question
Solve the quadratic equation
Solve using the quadratic formula
Solve by completing the square
Solve using the PQ formula
x1=26−38,x2=26+38
Alternative Form
x1≈−0.082207,x2≈6.082207
Evaluate
3(−31x×21)×2x=−1−(6x−21)
Simplify
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Evaluate
3(−31x×21)×2x
Multiply the terms
3(−61x)×2x
Rewrite the expression
−3×61x×2x
Multiply the terms
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Evaluate
3×61×2
Multiply the terms
21×2
Reduce the numbers
1×1
Simplify
1
−x×x
Multiply the terms
−x2
−x2=−1−(6x−21)
Subtract the terms
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Evaluate
−1−(6x−21)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
−1−6x+21
Add the numbers
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Evaluate
−1+21
Reduce fractions to a common denominator
−22+21
Write all numerators above the common denominator
2−2+1
Add the numbers
2−1
Use b−a=−ba=−ba to rewrite the fraction
−21
−21−6x
−x2=−21−6x
Move the expression to the left side
−x2+21+6x=0
Rewrite in standard form
−x2+6x+21=0
Multiply both sides
x2−6x−21=0
Multiply both sides
2(x2−6x−21)=2×0
Calculate
2x2−12x−1=0
Substitute a=2,b=−12 and c=−1 into the quadratic formula x=2a−b±b2−4ac
x=2×212±(−12)2−4×2(−1)
Simplify the expression
x=412±(−12)2−4×2(−1)
Simplify the expression
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Evaluate
(−12)2−4×2(−1)
Multiply
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Multiply the terms
4×2(−1)
Any expression multiplied by 1 remains the same
−4×2
Multiply the terms
−8
(−12)2−(−8)
Rewrite the expression
122−(−8)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
122+8
Evaluate the power
144+8
Add the numbers
152
x=412±152
Simplify the radical expression
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Evaluate
152
Write the expression as a product where the root of one of the factors can be evaluated
4×38
Write the number in exponential form with the base of 2
22×38
The root of a product is equal to the product of the roots of each factor
22×38
Reduce the index of the radical and exponent with 2
238
x=412±238
Separate the equation into 2 possible cases
x=412+238x=412−238
Simplify the expression
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Evaluate
x=412+238
Divide the terms
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Evaluate
412+238
Rewrite the expression
42(6+38)
Cancel out the common factor 2
26+38
x=26+38
x=26+38x=412−238
Simplify the expression
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Evaluate
x=412−238
Divide the terms
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Evaluate
412−238
Rewrite the expression
42(6−38)
Cancel out the common factor 2
26−38
x=26−38
x=26+38x=26−38
Solution
x1=26−38,x2=26+38
Alternative Form
x1≈−0.082207,x2≈6.082207
Show Solution
