How do I solve this? I know it's probably easy but i'm stupid?

Question

Solve 8r + 4(2r - 6) = 4r - 4

A. 8/3
B. 5/3
C. 3
D. 2

Answer 1

It is easy. But that doesn't mean your stupid. It just might not have been explained in a way that works for you, or it just may not have clicked for you yet.

I'm not going to solve your homework for you; that won't get you anywhere. But here's a basic way to proceed with algebra:

Take the problem one step
at a time. Don't worry about solving the whole thing at once, just look at one little piece and decide how you can make that simpler.

For example, in your problem, you've got:
8r.

This is as simple as it can get. You can't do anything with it, so go on to the next piece.

Then you have 4(2r - 6)
You can simplify this, since you can multiply it out. If you have A(B-C), this multiplies to AB-AC. You can always try real numbers to see if it works.

For example, what if you just had:
4(2-6)
If you subtracted first, you get 4(-4) = -16.
If you multiply first, you get (4*2) - (4*6) =
8 - 24 = -16.
Same answer.

Now, since you can't just subtract 6 from 2r to get a number, try multiplying them out.

Once you've done this, you'll have some numbers on their own, and some multiplied by r. You can add together the numbers, and you can add together the numbers that are multiplied by r. For example, if you had:
3r + 6 + 12r - 4 = 6r + 9
This simplifies to: 3r +12r + 6 - 4 = 6r + 9
Which simplifies to 15r + 2 = 6r +9
Then you get the variables on one side, and the numbers without variables on the other:
Subtract 6r from both sides and you get:
15r - 6r + 2 = 6r - 6r + 9
Which gets you 9r + 2 = 9
Now subtract 2 from both sides:
9r +2 - 2= 9 - 2
9r = 7.

No you can want to know what r is, so divide by 9 to get
r = 7/9.

Follow this same process with your numbers above, and you'll get the answer!

Answer 2

You start out with this:

8r + 4(2r-6) = 4r - 4

First, you need to focus on the parenthesis (PEMDAS). So you distribute the 4 to the (2r - 6)

Now, you have 8r + 8r - 24 = 4r - 4

Next, combine like terms. Add 8r + 8r to get 16 r.

16r - 24 = 4r - 4

Then, add 24 to the right side of the equation.

16r = 4r + 20

Subtract from the left side of the equation.

12r = 20

Divide the right side by 12.

r = 20/12

Simplify.

r = 5/3

If you want the steps typed out together:

8r + 4(2r-6) = 4r - 4
8r + 8r - 24 = 4r - 4
16r - 24 = 4r - 4
16r = 4r + 20
12r = 20
r = 20/12
r = 5/3

Your answer would be choice B.

Answer 3

8r + 4(2r - 6) = 4r - 4 , distribute the 4
8r + 8r - 24 = 4r - 4, combine like terms on the left side
16r - 24 = 4r - 4, subtract 4r from both sides
12r - 24 = -4, add 24 to both sides
12r = 20, divide both sides by 12
r = 20/12 = 5/3

Answer 4

Hi Hannah,

8r + 4(2r - 6) = 4r - 4

you need to distribute (the 4) and combine like therms

8r + 8r - 24 = 4r - 4
16r - 24 = 4r - 4
12r = 20
r = 20/12
r = 5/3

(B)

REgards,
Chas.

Answer 5

8r + 4(2r - 6) = 4r - 4
8r + 8r - 24 = 4r - 4
8r + 8r - 4r = -4 + 24
12r = 20
r = 20/12 = 5/3 or 1 2/3

HTH

Doug

Answer 6

distribute the 4:

8r + 4(2r) - 4(6) =
8r +8r -24= 4r -4

then you combine like terms and then isolate the r to solve for it:

16r -24 = 4r -4
12r = 20
B) r= 5/3

Answer 7

8r + 8r - 24 = 4r - 4 [expand the brackets]
16r - 4r = 24 - 4 [bring like terms to one side]
12r = 20
r = 20/12 [make r the subject]
r = 1/2/3 or 5/3


The answer is B.5/3

Answer 8

8r+4(2r-6)=4r-4
8r+8r-24=4r-4
16r-24=4r-4
+24 +24
16r=4r+20
-4r -4r
12r=20
12r/12=20/12
r=20/12 =5/3
r= 5/3

Answer 9

You just gotta know the rules:
Mult out the brackets then when amounts swap sides, change the sign:
8r + 8r -24 = 4r -4
16r-24=4r-4
16r -4r = 24-4
12r=20
r= 20/12=1.666 (5/3 i.e. B)

Answer 10

8r+4(2r-6)=4r-4
First you want to remove the paranthesis
8r+8r-24=4r-4
then add both 8r's together and add 24 on both sides to cancel it out on the left side
16r =4r+20
then subtract 4r on both sides to cancel it out on the right side
12r=20
then divde by 12
r=5/3