Respuesta :

Catya
how about: y = (x + 5)

6y^2 + 5y - 4 = 0

(2y - 1)(3y + 4) = 0

2y - 1 = 0
y = 1/2

3y + 4 = 0
y = -3/4

replace substitution, y = (x + 5)

1/2 = (x + 5)
-9/2 = x

-3/4 = (x + 5)
-23/4 = x

we have

[tex]6(x+5)^{2}+5(x+5)-4=0[/tex]

we know that

The equation of a quadratic equation is of the form

[tex]ax^{2} +bx+c=0[/tex]

so

Let

[tex]u=(x+5)[/tex]

Substitute

[tex]6(u)^{2}+5(u)-4=0[/tex]

therefore

the answer is

The substitution should be [tex]u=(x+5)[/tex]