Easy
quadratic means 2nd degree
means highest power of exponent is 2
so like x^2
first one
we have 3x^3, that is 3rd degree,nope
2nd one
we have 8x^4, nope, that is 4th degree
3rd one
we have -x^2, yep
4th one, we have 9x^4, that is 4th degree
answer is 3rd one or p(x)=-5x-x^2
Answer:

Step-by-step explanation:
Given that Lil's distance in 2/5 hrs is 2 3/4hrs
-Let x be the distance ran in 1 hr.
#We equate and cross multiply to solve for x as follows:

Hence, Lil can run 6 7/8 miles in 1 hr.
Step-by-step explanation:
Y=-4x+3
2x+3y=19
2x+3(-4x+3)=19
2x-12x+9=19
-10x=10
X=-1
y=-4*(-1)+3=4+3=7
x=-1 y=7
Answer:
It actually gave you the answer.
Step-by-step explanation:
If you read closer, it's telling you the answer. It's giving you examples of radicals and such.
Take this example (cause it's easy to explain)
10+5x=15x
To solve it we have to minus five on both side. We have to do this because we need to isolate the variable (in this case x) on the one side so we can divide and solve.
You would -5x (inverse from positive 5) from both sides on this because whatever you do to one side you have to do to the others to make it equal. In this case the answer would be x=1 (again cause it's easy lol.)
I hope this helps you!