Answer:
The factors are [tex]7,(x-2),(x+4)[/tex]
[tex]7x^{2} +14x-56=7(x-2)(x+4)[/tex]
Step-by-step explanation:
we have
[tex]7x^{2} +14x-56[/tex]
equate the expression to zero
[tex]7x^{2} +14x-56=0[/tex]
Group terms that contain the same variable, and move the constant to the opposite side of the equation
[tex]7x^{2} +14x=56[/tex]
Factor the leading coefficient
[tex]7(x^{2} +2x)=56[/tex]
[tex](x^{2} +2x)=8[/tex]
Complete the square. Remember to balance the equation by adding the same constants to each side
[tex](x^{2} +2x+1)=8+1[/tex]
[tex](x^{2} +2x+1)=9[/tex]
Rewrite as perfect squares
[tex](x+1)^{2}=9[/tex]
Take square root both sides
[tex](x+1)=(+/-)3[/tex]
[tex]x=-1(+/-)3[/tex]
[tex]x=-1(+)3=2[/tex]
[tex]x=-1(-)3=-4[/tex]
therefore
[tex]7x^{2} +14x-56=7(x-2)(x+4)[/tex]
