Algebra
Calculus
Trigonometry
Matrix
Question
Simplify the expression
x2+4x−21
Evaluate
(x+7)(x−3)
Apply the distributive property
x×x−x×3+7x−7×3
Multiply the terms
x2−x×3+7x−7×3
Use the commutative property to reorder the terms
x2−3x+7x−7×3
Multiply the numbers
x2−3x+7x−21
Solution
More Steps
Evaluate
−3x+7x
Collect like terms by calculating the sum or difference of their coefficients
(−3+7)x
Add the numbers
4x
x2+4x−21
Show Solution
Find the roots
x1=−7,x2=3
Evaluate
(x+7)(x−3)
To find the roots of the expression,set the expression equal to 0
(x+7)(x−3)=0
Separate the equation into 2 possible cases
x+7=0x−3=0
Solve the equation
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−3=0
Solve the equation
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=−7x=3
Solution
x1=−7,x2=3
Show Solution