Y=x^2-4x+8 and 4x+y=12 so y=12-4x, insert y in the quadratic to get
12-4x=x^2-4x+8
12=x^2+8
0=x^2-4=(x-2)(x+2)
So the solutions are x=2 and x=-2.
For this case we have the following inequality:

We multiply both sides of the equation by -1.
By doing this, change the symbol of the inequality.
We have then:

From here, we clear the value of x.
We have then:
Answer:
The solution set is:
{x | x R, x < -12}
Answer:
Answer is C. 3s + 9
Step-by-step explanation:
The perimeter is the sum of all 3 sides in a triangle
which is s+3 + s+3 + s+3
= 3s + 9