Question
Factor the expression
21(x−2)(2x+1)
Evaluate
x2−23x−1
Rewrite the expression
21×2x2−21×3x−21×2
Factor out 21 from the expression
21(2x2−3x−2)
Solution
More Steps

Evaluate
2x2−3x−2
Rewrite the expression
2x2+(1−4)x−2
Calculate
2x2+x−4x−2
Rewrite the expression
x×2x+x−2×2x−2
Factor out x from the expression
x(2x+1)−2×2x−2
Factor out −2 from the expression
x(2x+1)−2(2x+1)
Factor out 2x+1 from the expression
(x−2)(2x+1)
21(x−2)(2x+1)
Show Solution

Find the roots
x1=−21,x2=2
Alternative Form
x1=−0.5,x2=2
Evaluate
x2−23x−1
To find the roots of the expression,set the expression equal to 0
x2−23x−1=0
Factor the expression
More Steps

Evaluate
x2−23x−1
Rewrite the expression
21×2x2−21×3x−21×2
Factor out 21 from the expression
21(2x2−3x−2)
Factor the expression
More Steps

Evaluate
2x2−3x−2
Rewrite the expression
2x2+(1−4)x−2
Calculate
2x2+x−4x−2
Rewrite the expression
x×2x+x−2×2x−2
Factor out x from the expression
x(2x+1)−2×2x−2
Factor out −2 from the expression
x(2x+1)−2(2x+1)
Factor out 2x+1 from the expression
(x−2)(2x+1)
21(x−2)(2x+1)
21(x−2)(2x+1)=0
Divide the terms
(x−2)(2x+1)=0
When the product of factors equals 0,at least one factor is 0
x−2=02x+1=0
Solve the equation for x
More Steps

Evaluate
x−2=0
Move the constant to the right-hand side and change its sign
x=0+2
Removing 0 doesn't change the value,so remove it from the expression
x=2
x=22x+1=0
Solve the equation for x
More Steps

Evaluate
2x+1=0
Move the constant to the right-hand side and change its sign
2x=0−1
Removing 0 doesn't change the value,so remove it from the expression
2x=−1
Divide both sides
22x=2−1
Divide the numbers
x=2−1
Use b−a=−ba=−ba to rewrite the fraction
x=−21
x=2x=−21
Solution
x1=−21,x2=2
Alternative Form
x1=−0.5,x2=2
Show Solution
