Question
Solve the quadratic equation
Solve using the quadratic formula
Solve by completing the square
Solve using the PQ formula
x1=7−47,x2=7+47
Alternative Form
x1≈0.144345,x2≈13.855655
Evaluate
21x2=7x−1
Move the expression to the left side
21x2−7x+1=0
Multiply both sides
2(21x2−7x+1)=2×0
Calculate
x2−14x+2=0
Substitute a=1,b=−14 and c=2 into the quadratic formula x=2a−b±b2−4ac
x=214±(−14)2−4×2
Simplify the expression
More Steps

Evaluate
(−14)2−4×2
Multiply the numbers
(−14)2−8
Rewrite the expression
142−8
Evaluate the power
196−8
Subtract the numbers
188
x=214±188
Simplify the radical expression
More Steps

Evaluate
188
Write the expression as a product where the root of one of the factors can be evaluated
4×47
Write the number in exponential form with the base of 2
22×47
The root of a product is equal to the product of the roots of each factor
22×47
Reduce the index of the radical and exponent with 2
247
x=214±247
Separate the equation into 2 possible cases
x=214+247x=214−247
Simplify the expression
More Steps

Evaluate
x=214+247
Divide the terms
More Steps

Evaluate
214+247
Rewrite the expression
22(7+47)
Reduce the fraction
7+47
x=7+47
x=7+47x=214−247
Simplify the expression
More Steps

Evaluate
x=214−247
Divide the terms
More Steps

Evaluate
214−247
Rewrite the expression
22(7−47)
Reduce the fraction
7−47
x=7−47
x=7+47x=7−47
Solution
x1=7−47,x2=7+47
Alternative Form
x1≈0.144345,x2≈13.855655
Show Solution
