2x + 5 - 7x = 15I need help with the steps on how to work this problem.

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hala718's profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted on

2x + 5 - 7x = 15

First you need to group similar terms:

2x - 7x + 5 = 15

==> -5x + 5 = 15

Now subtract 5 from both sides:

==> -5x = 10

Now divide by -5 to free x :

==> x= 10/-5 = -2

==> x= -2

To check answer, substitute with x= -2 :

2x + 5 - 7x = 15

2*-2 + 5 - 7*-2 = 15

-4 + 5 +14 = 15

15 = 15

 

 

pohnpei397's profile pic

pohnpei397 | College Teacher | (Level 3) Distinguished Educator

Posted on

The answer to this is x = -2.  Here is how to go about doing this problem:

Remember that you are trying to get all the terms that have variables on one side of the equation and all the numbers on the other.  We'll start by doing that.  You can do that by subtracting 5 from both sides.  Then you have

2x - 7x = 10

So now you can simply subtract 7x from 2x.  That gives you

-5x = 10

Then, to get a value for x, you divide both sides by -5.  That gets you

x = -2

giorgiana1976's profile pic

giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted on

2x + 5 - 7x = 15

First, we'll combine like terms from the left side:

5 + (2x - 7x) = 15

5 - 5x = 15

Now, we'll factorize by 5, to the left side:

5(1-x) = 15

We'll divide by 5 both sides:

1 - x = 3

We'll isolate x to the lefts side. For this reason, we'll subtract 1 both sides:

-x = 3 - 1

-x = 2

We'll multiply by -1 both sides:

x = -2

The solution of the equation is x = -2.

william1941's profile pic

william1941 | College Teacher | (Level 3) Valedictorian

Posted on

We need to solve the equation 2x + 5 -7x = 15, for x.

Let's go about doing this with all the steps.

Take the equation:

2x + 5 -7x = 15

Add the terms containing x together.

=> -5x + 5 = 15

Subtract 5 from both the sides of the equation.

=> -5x + 5 - 5 = 15 - 5

=> -5x = 10

Divide both the sides of the equation by -5.

=> -5x/-5 = 10/-5

=> x = -2.

Therefore x = -2

neela's profile pic

neela | High School Teacher | (Level 3) Valedictorian

Posted on

2x+5-7x=15

2x and -7x on left are similars collect them together 2x-7x =-5x, and rewrite:

-5x+5 = 15.

Subtract 5.

-5x= 15-5

-5x = 10

Divide by -5.

-5x/-5 = 10/-5

x = -2.

Tally:

Put x = -2 in 2x+5-7x = 10.

LHS = 2*-2 +5 - 7*(-2)

= -4+5+14

= 1+15

= 15 = RHS

 

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