Answer: [tex]c=5[/tex]
Step-by-step explanation:
The Standard form of a Quadratic equation is:
[tex]ax^2+bx+c=0[/tex]
In this case, you need to find the value of "x" in Alessandro's quadratic equation. Then, you can add 6 to both sides of the equation in order to write it in Standard form:
[tex]-6+(6)=x^2+4x-1+(6)\\\\0=x^2+4x+5\\\\x^2+4x+5=0[/tex]
You can identify that the value of "c" in his equation is:
[tex]c=5[/tex]
