Answer:
40%
Step-by-step explanation:
10/25= x/100
25x=1000
25 divided by 1000 =40%
40x+8x^2=0 can be solved for x (there are two solutions):
Divide all 3 terms by the greatest common multiple (which is 8x):
40x+8x^2=0
------------- -----
8x 8x
5 + x = 0 produces the root x = - 5.
Setting 8x = 0 and solving for x produces the root x = 0.
Be certain to check these results. substitute x = -5 into 40x+8x^2=0. Is the resulting equation true or false? Next, subs. x=-5 into 40x+8x^2=0. Is the resulting equation true or false?
Answer:
x=1/2 y =1
Step-by-step explanation:
(-4x+2y)/2x5=0/2x5
10x+3y=8
(-2x+y)x5=0
10x+3y=8
-10x+5y=0
10x+3y=8
8y=8
y=1
x=1/2
You have a system of equations
![\left \{ {{y = -x^2+2x-9} \atop {y =-6x+6}} \right.](https://tex.z-dn.net/?f=%20%5Cleft%20%5C%7B%20%7B%7By%20%3D%20-x%5E2%2B2x-9%7D%20%5Catop%20%7By%20%3D-6x%2B6%7D%7D%20%5Cright.%20)
.
1. Substitude right side of second equation into the left side of the first equation:
![-6x+6=-x^2+2x-9](https://tex.z-dn.net/?f=-6x%2B6%3D-x%5E2%2B2x-9)
.
2. Solve this equation:
![x^2-2x+9-6x+6=0, \\ x^2-8x+15=0, \\ D=(-8)^2-4\cdot 1\cdot 15=64-60=4, \\ \sqrt{D}=2, \\ x_{1,2}=\dfrac{8\pm 2}{2 } =3,5](https://tex.z-dn.net/?f=x%5E2-2x%2B9-6x%2B6%3D0%2C%20%5C%5C%20x%5E2-8x%2B15%3D0%2C%20%5C%5C%20D%3D%28-8%29%5E2-4%5Ccdot%201%5Ccdot%2015%3D64-60%3D4%2C%20%20%5C%5C%20%5Csqrt%7BD%7D%3D2%2C%20%20%5C%5C%20x_%7B1%2C2%7D%3D%5Cdfrac%7B8%5Cpm%202%7D%7B2%20%20%7D%20%3D3%2C5)
.
3. Find y:
for
![x_1=3, y_1=-6\cdot 3+6=-18+6=-12](https://tex.z-dn.net/?f=x_1%3D3%2C%20y_1%3D-6%5Ccdot%203%2B6%3D-18%2B6%3D-12)
,
for
![x_2=5, y_2=-6\cdot 5+6=-30+6=-24](https://tex.z-dn.net/?f=x_2%3D5%2C%20y_2%3D-6%5Ccdot%205%2B6%3D-30%2B6%3D-24)
.
4. The solutions of the system are: (3,-12) and (5,-24).
Answer: Correct choice is A.