Marcus should have substituted -10for b, not 10
Marcus should have subtracted 4(1)(25) in the square root
This equation, when solved correctly, only has one real number solution
So A, C, D
Answer:
X=13
Step-by-step explanation:
So if ΔABC ≅ ΔDEC, then that means that ∠B is ≅ ∠E. Therefore you would write the equation 3x=6x-39 and solve for X to get 13.
Remember that the equation of a circle is:

Where (h, k) is the center and r is the radius.
We need to get the equation into that form, and find k.

Complete the square. We must do this for x² - 6x and y² - 10y separately.
x² - 6x
Divide -6 by 2 to get -3.
Square -3 to get 9. Add 9,
x² - 6x + 9
Because we've added 9 on one side of the equation, we have to remember to do the same on the other side.

Now factor x² - 6x + 9 to get (x - 3)² and do the same thing with y² - 10y.
y² - 10y
Divide -10 by 2 to get -5.
Square -5 to get 25.
Add 25 on both sides.

Factor y² - 10y + 25 to get (y - 5)²

Now our equation is in the correct form. We can easily see that h is 3 and k is 5. (not negative because the original equation has -h and -k so you must multiply -1 to it)
Since (h, k) represents the center, (3, 5) is the center and 5 is the y-coordinate of the center.
.725 , .572 , .275, .2
You look at the first decimal place to see which is the greatest. 7 is greater than 5 and 2 so it's first. Then 5 is greater than 2 so it is next. For the last two numbers since 2 is the same value you look at the next decimal place. Since 7 is greater than 0 it comes next!
Willy can cover in 1L paint

- 1st box should be filled with 4.5
Can cover in 10L

Second one should be filled with 45