Algebra
Calculus
Trigonometry
Matrix
Question
Factor the expression
(x−9)(x+2)
Evaluate
x2−7x−18
Rewrite the expression
x2+(2−9)x−18
Calculate
x2+2x−9x−18
Rewrite the expression
x×x+x×2−9x−9×2
Factor out x from the expression
x(x+2)−9x−9×2
Factor out −9 from the expression
x(x+2)−9(x+2)
Solution
(x−9)(x+2)
Show Solution
Find the roots
x1=−2,x2=9
Evaluate
x2−7x−18
To find the roots of the expression,set the expression equal to 0
x2−7x−18=0
Factor the expression
More Steps
Evaluate
x2−7x−18
Rewrite the expression
x2+(2−9)x−18
Calculate
x2+2x−9x−18
Rewrite the expression
x×x+x×2−9x−9×2
Factor out x from the expression
x(x+2)−9x−9×2
Factor out −9 from the expression
x(x+2)−9(x+2)
Factor out x+2 from the expression
(x−9)(x+2)
(x−9)(x+2)=0
When the product of factors equals 0,at least one factor is 0
x−9=0x+2=0
Solve the equation for x
More Steps
Evaluate
x−9=0
Move the constant to the right-hand side and change its sign
x=0+9
Removing 0 doesn't change the value,so remove it from the expression
x=9
x=9x+2=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=9x=−2
Solution
x1=−2,x2=9
Show Solution