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

Find the roots
x1=−1,x2=4
Evaluate
x2−3x−4
To find the roots of the expression,set the expression equal to 0
x2−3x−4=0
Factor the expression
More Steps

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

Evaluate
x−4=0
Move the constant to the right-hand side and change its sign
x=0+4
Removing 0 doesn't change the value,so remove it from the expression
x=4
x=4x+1=0
Solve the equation for x
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=4x=−1
Solution
x1=−1,x2=4
Show Solution
