Math again, algerbra?

Question

5 = 4(x - 7) + 3 - 2x

m + 9 = 3 \(4m - 6)

i really dont understand those.
i have exams so im studying all
of this. thanks for helping =)

Answer 1

OK, Let's take the first equation first. We always want to get rid of our parenthesis first if possible. So let's multiply 4 by x and -7 to get rid of the parenthesis. We'll rewrite our equation like this:

5 = 4x - 28 + 23 - 2x

Next thing we'll do is combine like terms. So...

5 = 4x - 2x + 23 - 28
5 = 2x -5

Now let's solve for x first by adding 5 to both sides to undo the -5.

5 (+5) = 2x -5 (+5) The -5 and +5 on the right of the = cancel

10 = 2x

Now let's divide both sides by 2 to undo the multiplication and to get x by itself.

10/2 = 2x/2 The 2's on the right of the = cancel

5 = x

That's your answer. Always remember, when dealing with an = what you do to one side must be done to the other side.

Let's look at your second problem:

Since we have a variable in the denominator let's multiply both sides by (4m-6) to get it out of there.

(m + 9)*(4m-6) = (3/4m-6) * (4m - 6) The (4m-6) on the right cancels

(m + 9)(4m - 6) = 3

Let's multiply through

m*4m + m*-6 + 9*4m + 9*-6 = 4m^2 -6m + 36m - 54

4m^2 -6m + 36m - 54 = 3

Combine like terms:

4m^2 + 30m - 54 = 3

Now here I assume you need to use the Quadratic Formula. So instead of adding 54 to both sides we'll subtract 3 from both sides to get our equation equal to 0

We have:
4m^2 + 30m - 57 = 0

The Quadratic Formula is: m = [-b +/- sqrt(b^2 - 4ac)] / 2a

a, b, and c represent the values of m^2, m, and the constant in your equation. So in your example, 4m^2 + 30m - 57 = 0, a would be 4, b would be 30 and c would be -37.

You would plug in your these values into the Quadratic Formula like this:

m = [-(30) +/- sqrt((30)^2 - 4(4)(-57))] / 2(4)

Now you can solve as a regular equation:

m = [-30 +/- sqrt(900 + 912)] / 8
m = [-30 + sqrt(1812)] / 8, [-30 - sqrt(1812)] / 8

I'm not sure how far you need to go but you can take it from here I'm sure. Hope this helps. Remember You will have TWO answers for this problem because you take the positive square root and the negative square root separately. Good Luck.

Answer 2

5=4(x-7)+3-2x 5=4x-28+3-2x 5=4x-2x-28+3 5=2x-25
25+5=2x-25+25 30=2x 30/2=2x/2 15=x
m+9=3/(4m-6) multiply both sides by 4m-6
(4m-6)(m+9)=3/(4m-6)x(4m-6)on this side the 4m-6 cancel each
other so your left with (4m-6)(m+9)=3
4m-6=3 m+9=3
4m=9 m=-6
m=9/4

Answer 3

5=4*x-4*7+3-2x
5=4x-28+3-2x
5+28-3=4x-2x
30=2x
x=30/2=15

m+9=3/4m-3/6
m-3/4m=-9-1/2
1/4m=-18/2-1/2=-19/2
multiply both sides by 4
m=-38

Answer 4

the first answer is x=15, as the other person stated..

Second one:

(4m-6)*(m+9)=3
4m^2+36m-6m-54=3
4m^2+30m-57=0
m=1.5709 and -9.0709

Answer 5

are you sure the second equation is correct ?

first one is x = 15

Yea, I had to plug the formula into the calculator to get this answer. Answer of guy below is right... m=1.57 and m = -9.070. I think this is just a simple quadratic equation with whole answers. Maybe you type it incorrectly.