Answer:
there are 80 students
Step-by-step explanation:
you divide 9 by 90 to find how many teachers there are, then subtract it by 90
Just subtract 291.5 from 366.6
the answer is 75.1 dollars
So for this, I will be using the substitution method. Firstly, subtract both sides in the second equation by 2x: 
Next, substitute y in the first equation with 7-2x, then solve for x from there:
Now that we got x, substitute it into either equation to solve for y:
In short, x = 1/2 and y = 6.
Take the second equation and flip it around so the y on the left ends up on the right and the 4x on the right ends up on the left. This makes all negatives positive and all positives negative. -4x + 12 = y
Then add the first equation to the second equation
4x +12 = -7y
<u>-4x + 12 </u>=<u> y </u> this eliminates the x's
<u>24</u> = -<u> 6y</u> then divide by - 6
- 6 - 6
- 4 = y<u>
</u>So if you know that y = negative 4, you can substitute into either equation. I pick the second one because I am a lazy person.
-y + 12 = 4 x
-(-4) + 12 = 4 x combine your numbers<u>
</u> <u> 16 </u> = <u>4 x </u> then divide by 4<u>
</u> 4 = x
So your solution is: x = 4 and y = -4 or this is also written (4, -4)
Does that work for you?
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
