Algebra
Calculus
Trigonometry
Matrix
Question
Factor the expression
(b−9)(b+5)
Evaluate
b2−4b−45
Rewrite the expression
b2+(5−9)b−45
Calculate
b2+5b−9b−45
Rewrite the expression
b×b+b×5−9b−9×5
Factor out b from the expression
b(b+5)−9b−9×5
Factor out −9 from the expression
b(b+5)−9(b+5)
Solution
(b−9)(b+5)
Show Solution
Find the roots
b1=−5,b2=9
Evaluate
b2−4b−45
To find the roots of the expression,set the expression equal to 0
b2−4b−45=0
Factor the expression
More Steps
Evaluate
b2−4b−45
Rewrite the expression
b2+(5−9)b−45
Calculate
b2+5b−9b−45
Rewrite the expression
b×b+b×5−9b−9×5
Factor out b from the expression
b(b+5)−9b−9×5
Factor out −9 from the expression
b(b+5)−9(b+5)
Factor out b+5 from the expression
(b−9)(b+5)
(b−9)(b+5)=0
When the product of factors equals 0,at least one factor is 0
b−9=0b+5=0
Solve the equation for b
More Steps
Evaluate
b−9=0
Move the constant to the right-hand side and change its sign
b=0+9
Removing 0 doesn't change the value,so remove it from the expression
b=9
b=9b+5=0
Solve the equation for b
More Steps
Evaluate
b+5=0
Move the constant to the right-hand side and change its sign
b=0−5
Removing 0 doesn't change the value,so remove it from the expression
b=−5
b=9b=−5
Solution
b1=−5,b2=9
Show Solution