Algebra
Calculus
Trigonometry
Matrix
Question
Factor the expression
(4−x)(5+x)
Evaluate
20−x−x2
Rewrite the expression
20+(4−5)x−x2
Calculate
20+4x−5x−x2
Rewrite the expression
4×5+4x−x×5−x×x
Factor out 4 from the expression
4(5+x)−x×5−x×x
Factor out −x from the expression
4(5+x)−x(5+x)
Solution
(4−x)(5+x)
Show Solution
Find the roots
x1=−5,x2=4
Evaluate
20−x−x2
To find the roots of the expression,set the expression equal to 0
20−x−x2=0
Factor the expression
More Steps
Evaluate
20−x−x2
Rewrite the expression
20+(4−5)x−x2
Calculate
20+4x−5x−x2
Rewrite the expression
4×5+4x−x×5−x×x
Factor out 4 from the expression
4(5+x)−x×5−x×x
Factor out −x from the expression
4(5+x)−x(5+x)
Factor out 5+x from the expression
(4−x)(5+x)
(4−x)(5+x)=0
When the product of factors equals 0,at least one factor is 0
4−x=05+x=0
Solve the equation for x
More Steps
Evaluate
4−x=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
Change the signs on both sides of the equation
x=4
x=45+x=0
Solve the equation for x
More Steps
Evaluate
5+x=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=4x=−5
Solution
x1=−5,x2=4
Show Solution