Question
Solve the quadratic equation
Solve using the quadratic formula
Solve by completing the square
Solve using the PQ formula
y1=1−2,y2=1+2
Alternative Form
y1≈−0.414214,y2≈2.414214
Evaluate
y2−2y=1
Move the expression to the left side
y2−2y−1=0
Substitute a=1,b=−2 and c=−1 into the quadratic formula y=2a−b±b2−4ac
y=22±(−2)2−4(−1)
Simplify the expression
More Steps

Evaluate
(−2)2−4(−1)
Simplify
(−2)2−(−4)
Rewrite the expression
22−(−4)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
22+4
Evaluate the power
4+4
Add the numbers
8
y=22±8
Simplify the radical expression
More Steps

Evaluate
8
Write the expression as a product where the root of one of the factors can be evaluated
4×2
Write the number in exponential form with the base of 2
22×2
The root of a product is equal to the product of the roots of each factor
22×2
Reduce the index of the radical and exponent with 2
22
y=22±22
Separate the equation into 2 possible cases
y=22+22y=22−22
Simplify the expression
More Steps

Evaluate
y=22+22
Divide the terms
More Steps

Evaluate
22+22
Rewrite the expression
22(1+2)
Reduce the fraction
1+2
y=1+2
y=1+2y=22−22
Simplify the expression
More Steps

Evaluate
y=22−22
Divide the terms
More Steps

Evaluate
22−22
Rewrite the expression
22(1−2)
Reduce the fraction
1−2
y=1−2
y=1+2y=1−2
Solution
y1=1−2,y2=1+2
Alternative Form
y1≈−0.414214,y2≈2.414214
Show Solution
