Algebra
Calculus
Trigonometry
Matrix
Question
Factor the expression
(x−7)(x+4)
Evaluate
x2−3x−28
Rewrite the expression
x2+(4−7)x−28
Calculate
x2+4x−7x−28
Rewrite the expression
x×x+x×4−7x−7×4
Factor out x from the expression
x(x+4)−7x−7×4
Factor out −7 from the expression
x(x+4)−7(x+4)
Solution
(x−7)(x+4)
Show Solution
Find the roots
x1=−4,x2=7
Evaluate
x2−3x−28
To find the roots of the expression,set the expression equal to 0
x2−3x−28=0
Factor the expression
More Steps
Evaluate
x2−3x−28
Rewrite the expression
x2+(4−7)x−28
Calculate
x2+4x−7x−28
Rewrite the expression
x×x+x×4−7x−7×4
Factor out x from the expression
x(x+4)−7x−7×4
Factor out −7 from the expression
x(x+4)−7(x+4)
Factor out x+4 from the expression
(x−7)(x+4)
(x−7)(x+4)=0
When the product of factors equals 0,at least one factor is 0
x−7=0x+4=0
Solve the equation for x
More Steps
Evaluate
x−7=0
Move the constant to the right-hand side and change its sign
x=0+7
Removing 0 doesn't change the value,so remove it from the expression
x=7
x=7x+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=7x=−4
Solution
x1=−4,x2=7
Show Solution