Question
Factor the expression
(x−5)(7x+4)
Evaluate
7x2−31x−20
Rewrite the expression
7x2+(4−35)x−20
Calculate
7x2+4x−35x−20
Rewrite the expression
x×7x+x×4−5×7x−5×4
Factor out x from the expression
x(7x+4)−5×7x−5×4
Factor out −5 from the expression
x(7x+4)−5(7x+4)
Solution
(x−5)(7x+4)
Show Solution

Find the roots
x1=−74,x2=5
Alternative Form
x1=−0.5˙71428˙,x2=5
Evaluate
7x2−31x−20
To find the roots of the expression,set the expression equal to 0
7x2−31x−20=0
Factor the expression
More Steps

Evaluate
7x2−31x−20
Rewrite the expression
7x2+(4−35)x−20
Calculate
7x2+4x−35x−20
Rewrite the expression
x×7x+x×4−5×7x−5×4
Factor out x from the expression
x(7x+4)−5×7x−5×4
Factor out −5 from the expression
x(7x+4)−5(7x+4)
Factor out 7x+4 from the expression
(x−5)(7x+4)
(x−5)(7x+4)=0
When the product of factors equals 0,at least one factor is 0
x−5=07x+4=0
Solve the equation for x
More Steps

Evaluate
x−5=0
Move the constant to the right-hand side and change its sign
x=0+5
Removing 0 doesn't change the value,so remove it from the expression
x=5
x=57x+4=0
Solve the equation for x
More Steps

Evaluate
7x+4=0
Move the constant to the right-hand side and change its sign
7x=0−4
Removing 0 doesn't change the value,so remove it from the expression
7x=−4
Divide both sides
77x=7−4
Divide the numbers
x=7−4
Use b−a=−ba=−ba to rewrite the fraction
x=−74
x=5x=−74
Solution
x1=−74,x2=5
Alternative Form
x1=−0.5˙71428˙,x2=5
Show Solution
