help help help?

Question

24. Use the completing the square method to find the roots of 3x2 - 6x - 24 = 0.
A. 4, -2
B. 4, 2
C. -4, -2
D. -4, 2
25. Find the roots of x2 - 6x + 8 = 0 by completing the square.
A. 2, 4
B. 2, -4
C. -2, 4
D. -2, -4
26. Use the completing the square method to find the roots of 4x2 + 28x = 32.
A. 8, 1
B. 8, -1
C. -8, 1
D. -8, -1
27. Use the completing the square method to find the roots of x2 = -6x - 5.
A. -1, -5
B. -1, 5
C. 1, -5
D. 1, 5
28. Find the roots of x2 + 2x = 15 by completing the square.
A. 3, -5
B. 3, 5
C. -3, -5
D. -3, 5
29. Find the roots of x2 - 3x = 18 by completing the square.
A. -6, -3
B. -6, 3
C. 6, 3
D. 6, -3
30. Use the completing the square method to find the roots of x2 - 12 = 4x.
A. -6, -2
B. -6, 2
C. 6, 2
D. 6, -2
31. Use the quadratic formula to find the roots of 2x2 - 3x - 2 = 0.
A. 1/2, 2
B. -1/2
C. -4
D. 0

im not a student im a lift teacher i work for Ecot

Answer 1

3x2 - 6x - 24 = 0
To complete the square, first move all the constants to the opposite side.

3x^2 - 6x = 24

Next, multiply or divide to make the coefficient of the x^2 term 1. In this case, divide through by 3

x^2 - 2x = 8

Now, take 1/2 of the coefficient of the "x" term, square it, and add it to both sides. In fact, you don't even have to square it out, just write it in as squared. 1/2 of 2 is 1.

x^2 - 2x + 1^2 = 8+1^2

The left hand side is now a perfect square. Factor it:

(x - 1)^2 = 9

Take the square root of both sides

(x-1) = +/- sqrt(9) = +/- 3

Solve for x:

x = 1 + 3 and x = 1-3
x = 4; x= -2

Now try to do the rest. If you get stuck, you can email me.

Answer 2

24. Use the completing the square method to find the roots of 3x2 - 6x - 24 = 0.

I'll show you how to do this so you can do the rest yourself.

First divide by 3 getting:
x^2 -2x -8 =0

Look at the number multiplying x, it is 2. Divide it by 2, getting 1.
Now square 1 getting 1.

Now add the 1 to both sides of the equation getting:
x^2 -2x+1 -8 = 1
Add 8 to both sides getting:
x^2 -2x +1 = 9
(x-1)^2 = 9 [X^2 -2x +1 is the perfect square we just completed]
Take square root of both sides getting:
x-1 = +/- 3
x = 1 +/- 3
x= 1+3 = 4 and
x = 1 - 3 = -2

Summarizing, divide equation, if necessary, by the number multiplying x^2. You'll need to do this on problems 26 and 31.

The take the number multiplying the x term, divide it by 2 and square it.

Add this number to both sides of the equation.

When you do this, the x^2 + the xterm + the nunber you adde will form a perfect square .

Move everything else to the rught hand side and cahnge their sign.

Take the square root of both sides

You should get two answers since the sqrt of the Right side will be +/-.

Hope this helped you to solve completing the square programs by yourself.

Answer 3

Sweetie, you need to do your own homework. The very act of struggling to understand will help you to learn. Don't expect answers on a silver platter.....
If you really have no idea how to solve these problems, ask your teacher or get a good study buddy.

Answer 4

sorry, but, if we help you now, when you have to do something independant like a test you may do bad. do it yourself, and if you need help ask someone on what you don't get and what you learn use it in the homework.

Answer 5

do your own homework that is the only way you are going to learn

Answer 6

we're not here to do your math homework for you. learn to do it yourself.