Algebra
Calculus
Trigonometry
Matrix
Question
Factor the expression
(x−42)(x+3)
Evaluate
x2−39x−126
Rewrite the expression
x2+(3−42)x−126
Calculate
x2+3x−42x−126
Rewrite the expression
x×x+x×3−42x−42×3
Factor out x from the expression
x(x+3)−42x−42×3
Factor out −42 from the expression
x(x+3)−42(x+3)
Solution
(x−42)(x+3)
Show Solution
Find the roots
x1=−3,x2=42
Evaluate
x2−39x−126
To find the roots of the expression,set the expression equal to 0
x2−39x−126=0
Factor the expression
More Steps
Evaluate
x2−39x−126
Rewrite the expression
x2+(3−42)x−126
Calculate
x2+3x−42x−126
Rewrite the expression
x×x+x×3−42x−42×3
Factor out x from the expression
x(x+3)−42x−42×3
Factor out −42 from the expression
x(x+3)−42(x+3)
Factor out x+3 from the expression
(x−42)(x+3)
(x−42)(x+3)=0
When the product of factors equals 0,at least one factor is 0
x−42=0x+3=0
Solve the equation for x
More Steps
Evaluate
x−42=0
Move the constant to the right-hand side and change its sign
x=0+42
Removing 0 doesn't change the value,so remove it from the expression
x=42
x=42x+3=0
Solve the equation for x
More Steps
Evaluate
x+3=0
Move the constant to the right-hand side and change its sign
x=0−3
Removing 0 doesn't change the value,so remove it from the expression
x=−3
x=42x=−3
Solution
x1=−3,x2=42
Show Solution