Algebra
Calculus
Trigonometry
Matrix
Question
Factor the expression
(x+1)(x2−x−1)
Evaluate
x3−2x−1
Calculate
x3−x2−x+x2−x−1
Rewrite the expression
x×x2−x×x−x+x2−x−1
Factor out x from the expression
x(x2−x−1)+x2−x−1
Solution
(x+1)(x2−x−1)
Show Solution
Find the roots
x1=−1,x2=21−5,x3=21+5
Alternative Form
x1=−1,x2≈−0.618034,x3≈1.618034
Evaluate
x3−2x−1
To find the roots of the expression,set the expression equal to 0
x3−2x−1=0
Factor the expression
(x+1)(x2−x−1)=0
Separate the equation into 2 possible cases
x+1=0x2−x−1=0
Solve the equation
More Steps
Evaluate
x+1=0
Move the constant to the right-hand side and change its sign
x=0−1
Removing 0 doesn't change the value,so remove it from the expression
x=−1
x=−1x2−x−1=0
Solve the equation
More Steps
Evaluate
x2−x−1=0
Substitute a=1,b=−1 and c=−1 into the quadratic formula x=2a−b±b2−4ac
x=21±(−1)2−4(−1)
Simplify the expression
More Steps
Evaluate
(−1)2−4(−1)
Evaluate the power
1−4(−1)
Simplify
1−(−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
1+4
Add the numbers
5
x=21±5
Separate the equation into 2 possible cases
x=21+5x=21−5
x=−1x=21+5x=21−5
Solution
x1=−1,x2=21−5,x3=21+5
Alternative Form
x1=−1,x2≈−0.618034,x3≈1.618034
Show Solution