Question
Factor the expression
Factor
4(x−5)(x+4)
Evaluate
4x2−4x−80
Rewrite the expression
4x2−4x−4×20
Factor out 4 from the expression
4(x2−x−20)
Solution
More Steps
Evaluate
x2−x−20
Rewrite the expression
x2+(4−5)x−20
Calculate
x2+4x−5x−20
Rewrite the expression
x×x+x×4−5x−5×4
Factor out x from the expression
x(x+4)−5x−5×4
Factor out −5 from the expression
x(x+4)−5(x+4)
Factor out x+4 from the expression
(x−5)(x+4)
4(x−5)(x+4)
Show Solution
Find the roots
Find the roots of the algebra expression
x1=−4,x2=5
Evaluate
4x2−4x−80
To find the roots of the expression,set the expression equal to 0
4x2−4x−80=0
Factor the expression
More Steps
Evaluate
4x2−4x−80
Rewrite the expression
4x2−4x−4×20
Factor out 4 from the expression
4(x2−x−20)
Factor the expression
More Steps
Evaluate
x2−x−20
Rewrite the expression
x2+(4−5)x−20
Calculate
x2+4x−5x−20
Rewrite the expression
x×x+x×4−5x−5×4
Factor out x from the expression
x(x+4)−5x−5×4
Factor out −5 from the expression
x(x+4)−5(x+4)
Factor out x+4 from the expression
(x−5)(x+4)
4(x−5)(x+4)
4(x−5)(x+4)=0
Divide the terms
(x−5)(x+4)=0
When the product of factors equals 0,at least one factor is 0
x−5=0x+4=0
Solve the equation for x
More Steps
Evaluate
x−5=0
Move the constant to the right-hand side and change its sign
x=0+5
Removing 0 doesn't change the value,so remove it from the expression
x=5
x=5x+4=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=5x=−4
Solution
x1=−4,x2=5
Show Solution