Question

Solve by factoring 5x^3 - 80x=0

Answer 1

is there an anser choice

Answer 2

no

Answer 3

i got this x=4

Answer 4

oh wait my teacher got -4,0,4

Answer 5

\[5x^3-80x=0\]\[5x(x^2-16)=0\]\[5x(x-4)(x+4)=0\]\[x=0,4,-4\]

Answer 6

same thing i got

Answer 7

@jagr2713 This is a cubic equation, therefore you should have three solutions not just one.

Answer 8

oh i got this look

Answer 9

Factor out the GCF of 5x from the expression 5x3.

5x(x2)−80x=0


Factor out the GCF of 5x from the expression −80x.

5x(x2)+5x(−16)=0


Factor out the GCF of 5x from 5x3−80x.

5x(x2−16)=0


The binomial can be factored using the difference of squares formula, because both terms are perfect squares.

5x(x+4)(x−4)=0

5x(x+4)(x−4)=0

Set the single term factor on the left-hand side of the equation equal to 0.

5x=0

Divide each term in the equation by 5.

More Detail
Divide each term in the equation by 5.

5x5=05


Cancel the common factor of 5 in 5x5.

1 5 x 5 =05


Reduce the expression 5x5 by removing a factor of 5 from the numerator and denominator.

x=05


0 divided by any number or variable is 0.

x=0

x=0

Set each of the factors of the left-hand side of the equation equal to 0.

x+4=0
x−4=0

Solve the equations for x.


Since 4 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 4 from both sides.

x=−4
x−4=0


Set each of the factors of the left-hand side of the equation equal to 0.

x=−4
x−4=0


Since −4 does not contain the variable to solve for, move it to the right-hand side of the equation by adding 4 to both sides.

x=−4
x=4


Solve the equations for x.

x=0,−4,4

x=0,−4,4