Are you good at math?

Question

I am when it's explained well, and this wasn't. So could you help me out?

13x + 7 = 5x - 20

ok so I know that the answer is x = -3 3/8
but how do you figure it out???? I found out the answer by looking it up and it doesn't explain it really well.
Thanks.

Brunette Poet ;)

Answer 1

13x + 7 = 5x - 20
8x + 7 = -20 subtract 5x from both sides
8x = -27 subtract 7 from both sides
x = -27/8 = -3 3/8 divide and simplify

Answer 2

13x + 7 = 5x - 20

Put all the numbers with x on the same side (term is "isolate x)
by subtracting 5x from both sides
13x -5x + 7 = 5x - 5x -20
simplifies to
13x -5x + 7 = - 20
Then get all the numbers without x on same side
by subtracting 7 from both sides
13x - 5x +7 - 7 = -20 - 7
simplifies to
13x - 5x = -20 - 7
Now do the adding and subtracting
8x = - 27
Divide both sides by 8 to isolate x all by itself
x = -27/8
Then get it down to the lowest form: 8 goes into 27 3 times (8*3 = 24) with 3 remaining giving:
x = -3 3/8

I hope that was broken down enough. In "real life" you would do alot of these steps in your head and not write them down but I wanted you to see every little step.

Best of Luck.
:)

Answer 3

Looks simple. See the following steps.
Bring all the x's to one side and the constants to the other
=> 13x - 5x = -20 - 7

Simplifying ,

8x = -27

x = -27/8

Changing this answer to mixed fraction , it becomes,

8 ) 27 ( 3
24
-------------
3 --> remainder

Expressing the asnwer in mixed fraction method , it becomes

- 3 3/8 ( The first 3, is the quotient, 3 in the fraction is the remainder and 8 is the divident )

Answer 4

Well, here goes:

In algebra, it's about trying to reduce the equation to a form that is easily solvable. So first we start by moving all our variables to one side of the equation, conventionally the right hand side (RHS). To do this, we subtract both sides of the equation by 5x.

13x - 5x + 7 = 5x - 5x - 20

and you'd get

8x + 7 = -20

Also, we move our knowns to the left hand side (LHS). Thus we subtract 7 on both sides of the equation

8x +7 - 7 = -20 -7

to get

8x = -27

Now, in order to find x, our variable, we divide both sides by 8. Hence,

8x / 8 = -27 / 8

to get

x = -27/8

where -27/8 is equivalent to -3 3/8. Always think in terms of simplifying your equation so that all your knowns are on one side and your variables (such as x in this case) on the other. It's that simple. Good luck

Answer 5

am a little good at it
just take 5x to left hand side, its sign would change and it will be
13x + 7 - 5x = -20
similarly take 7 to right hand side
13x - 5x = -20 -7
solving it
8x = -27
taking 8 to right hand side, it will divide -27 (sign changes when we change side)
therefore, x = -27/8
splitting 27: 3 * 8 = 24 + 3 =27
=> -3 3/8
[cause 8 (denominator) will be multiplied by the whole number 3 and the numerator would be added which will give the result -27/8]

Answer 6

13x + 7 = 5x - 20
since it's an equation - what ever we do is to BOTH sides
keeping it an equation....first we need to get the x on one side
subtract 5x from both sides
8x + 7 = - 20.......now we need to get the 7 out of there so
subtract 7 from both sides
8x = - 27.....now divide both sides by 8
x = -27/8 = - 3 3/8

tada ! now you see how to do it!

Answer 7

hold on (sorry i type slow)
edit: OK so first you want to get all of your X's on the same side, and all of your numbers on the same side
you start by taking the 5x and subtracting it from both sides 9remember what you do to one side you must do to the other)
on the one side this will cancel out the 5x and on the other it will be subtracted from the 13x to get
8x + 7 = -20
next, since you have your X's on the left, move your numbers to the right. so to do this you will minus 7 to both sides. this will cancel out the 7 on the one side and give you -27 on the other
now you have 8x= -27
if you have gotten the pattern by now to cancel out that 8 on the left you need to do the opposite. since x is being multiplied by the 8 you divide the 8 by both sides. this cancels out the 8 on the left and leaves you with -3 and 3/8
now what do you have? tada x+ -3 and 3/8
hope i helped!

Answer 8

well since 13x + 7 = 5x - 20
13x - 5x = -20 - 7
8x = -27
x= -27/8

nd..-27/8 = -3 3/8

Answer 9

get your variables on one side and your numbers on the other.
13x + 7 = 5x - 20
13x-5x = -20-7
8x=-27
x = -27/8

Answer 10

I am.

8x=-27, hmm

x=-27/8