Factor the quadratic expression completely.
3x^2 – 20x – 7=

The final solution is all the values that make  

(3 x+1) (x−7)=0  true.x = −13,7

Step-by-step explanation:

Factor −20 out of −20 x .3 x 2−20 x−7=0

Rewrite −20 as 1 plus −213 x 2+(1−21)x−7=0

Apply the distributive property.3 x 2+1 x−21 x−7=0

Multiply x by 1.3 x 2+ x−21 x−7=0

Factor out the greatest common factor from each group.

Group the first two terms and the last two terms.

(3 x 2+ x)−21 x−7=0

Factor out the greatest common factor (GCF) from each group.

x(3 x+1)−7(3 x+1)=0

Factor the polynomial by factoring out the greatest common factor,

3 x +1.(3 x+1)(x−7)=0

If any individual factor on the left side of the equation is equal to

0 , the entire expression will be equal to

0.3 x+1=0 x−7=0

Set the first factor equal to

0 and solve.

x=−13

Set the next factor equal to

0

and solve.

Set the next factor equal to

0.x−7=0

Add

7 to both sides of the equation.

x=7