Question

Quais são os zeros(ou raízes) da função quadrática f(x) = x² + 3x - 4? Assinale a alternativa correta. *

Answer 1

Given:

The quadratic function is:

$f(x)=x^2+3x-4$

To find:

The zeros of the given quadratic function.

Solution:

We have,

$f(x)=x^2+3x-4$

Splitting the middle term, we get

$f(x)=x^2+4x-x-4$

$f(x)=x(x+4)-1(x+4)$

$f(x)=(x+4)(x-1)$

For zeros, $f(x)=0$.

$(x+4)(x-1)=0$

$x=-4,1$

Therefore, the correct option is (b).