Please Help With Maths Questions?

Question

please help. My substatute teacher keeps giving the class questions that she hasn't even teached us to do yet. Please help!

Solve:
1) x-2x=-8
2)6x squared-x-2=0
3)9x squared-9x-28=0
4)6x squared+x-2=0
5)4x squared-9=0

Please Help ASAP!!!

Answer 1

1) x^2 - 2x + 8 = 0
(x - 4)(x + 2) = 0
x = {-2, 4}

2) 6x^2 - x - 2 = 0
(3x - 2)(2x + 1) = 0
x = {-1/2, 2/3}

3) 9x^2 - 9x - 28 = 0
(3x - 7)(3x + 4) = 0
x = {-4/3, 7/3}

4) 6x^2 + x - 2 = 0
(3x + 2)(2x - 1) = 0
x {-2/3, 1/2}

5) 4x^2 - 9 = 0
(2x + 3)(2x - 3) = 0
x = {-3/2, 3/2}

The first link in the source will show you how to do these step by step. Read it and your math book. Also look into getting a tutor. You won't have Yahoo! Answers to help you during tests.
The calculator in the source will help you check your answers.

P.S. Substitute is the correct spelling. Taught is the past tense of the verb to teach.

Answer 2

I tried to work these problems in the most broken down steps possible so that you can analyze my solving process.

1) -x = 8 (combining the x and -2x terms)
x = 8 (dividing both sides by -1)

2) (3x-2) (2x+1) = 0 (factoring the binomial)
3x - 2 = 0 or 2x + 1 = 0
3x = 2 2x = -1
x = 2/3 or x = -1/2

3) (3x -7)(3x +4) = 0
3x - 7 = 0 or 3x + 4 = 0
3x = 7 or 3x = -4
x = 7/3 or x = -4/3

4) (3x + 2) (2x - 1) = 0
3x + 2 = 0 or 2x - 1 = 0
3x = -2 or 2x = 1
x = -2/3 or x = 1/2

5) (2x - 3) (2x + 3) = 0
2x - 3 = 0 or 2x + 3 = 0
2x = 3 or 2x = -3
x = 3/2 or x = -3/2

Answer 3

1) combine the x's
-x = -8 (now divide by a negative one so the x becomes possitive)
x = 8

2) you have to factor it out
6x^2 - x - 2 =0
(3x - 2) (2x +1) = 0
now you set each part equal to 0, you will get 2 answers for this problem.
3x - 2 = 0
3x = 2 (added 2 to both sides to get the x alone)
x = 2/3 (divided both sides by 3)
2x + 1 = 0
2x = -1
x = -1/2
so the answer is x = (2/3) and (-1/2)

I am going to let you try the rest of them. good luck

Answer 4

"Teached us?" why don't you focus more in school...

I'll help but I won't tell you the answers, just how to do it:

1.) x-2x= -1x (Just subtract the x's like regular numbers)
-1x= -8, and from there you can hopefully figure out what x is...
2.-5.) All you have to do is get the first half of the problem to equal the opposite of the second half.

6x squared-x has to equal 2. This is because nothing else minus 2= 0.

Same thing for the rest of them.

Hope this helps!

Answer 5

1) x=-8
2)x= 2/3 x=-1/2
3)x=7/3 x=-4/3
4)x=-2/3 x=1/2
5)x=-3/2 x=3/2

Answer 6

The trick is to move numbers and variables around to get "x" by itself on one side:

1) x-2x = -8 ---> -x = -8 ---> x = 8

The others are more tricky, and you should have someone sit down with you and explain to you how they are done.

Answer 7

it's impossible. You need to know what x =