Respuesta :

Answer:

-77

Step-by-step explanation:

2x-1=13

2x=13+1=14

x=14/2=7

[tex]-x^2-4x=-(7)^2-4(7)=-49-28=-77[/tex]

Answer:

- 77

Step-by-step explanation:

The given expression is -x^2-4x; there is another expression (2x - 1 = 13), which can be solved for x as follows:

2x - 1 = 13  

Adding 1 to both sides, we get:  

2x = 14

Dividing both sides by 2 results in:  x = 7

Substituting 7 for x in   -x^2-4x   yields   -(7)^2-4(7), or:

-49 - 28, or -77