algebraic equation?

Question

If 8x+5(3+x)-a=15+5x, then a=?

Answer 1

8x+5(3+x)-a=15+5x

1.) Subtract (15 + 5x) from both sides.
8x+5(3+x)-a - 15 - 5x =15+5x - 15 - 5x
8x+5(3+x)-a - 15 - 5x =0

2.) Multiply out 5(3+x).
8x+5(3+x)-a - 15 - 5x =0
8x+15+5x -a - 15 - 5x =0

3.) Combine like terms.
8x+15+5x -a - 15 - 5x =0
8x+5x - 5x + 15 - 15 - a =0
8x - a =0

4.) Add a to both sides.
8x - a =0
8x - a + a =0 + a
8x = a
a = 8x (solution)

Answer 2

8x+5(3+x)-a=15+5x

First, let's work on the left hand side of your equation, the 8x+5(3+x)-a
This means, for instance, to see if it can be simplified at all.
Multiply x and 8
Multiply x and 1

Ok, this goes here...
The x just gets copied along.

8x
3+x
we multiply 5 by each term in 3+x term by term.
This is the distributive property of multiplication.

Multiply 5 and 3
1
5 × 3 = 15
Multiply 5 and x
Multiply 1 and x
The x just gets copied along.

5 × x = 5x

15+5x

8x + 5x = 13x

So, all-in-all, the left hand side of your equation can be written as: 13x+15-a

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Now, let's work on the right hand side of your equation, the 15+5x
Multiply x and 5
Multiply x and 1

The x just gets copied along.

The right hand side of your equation can be written as: 15+5x

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So with these (any) simplifications, the equation we'll set out to solve is:

13x+15-a = 15+5x

Move the 13x to the right hand side by subtracting 13x from both sides, like this:

From the left hand side:
13x - 13x = 0

I'm working on your answer...
15-a

From the right hand side:
5x - 13x = -8x

Let's see, ummmm...
-8x+15

Now, the equation reads:
15-a = -8x+15

Move the 15 to the right hand side by subtracting 15 from both sides, like this:

From the left hand side:
15 - 15 = 0

Checking out what you typed...
-a
From the right hand side:
15 - 15 = 0

-8x

Now, the equation reads:
-a = -8x

To isolate the a, we have to divide both sides of the equation by the other variables around the a on the left side of the equation.

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The last step is to divide both sides of the equation by -1 like this:

To divide a by 1

The a just gets copied along in the numerator.

Doing a bit of algebra...

a
-a ÷ -1 = a

To divide x by 1
The x just gets copied along in the numerator.

-8x ÷ -1 = 8x

The solution to your equation is:
a = 8x

Answer 3

8x+5(3+x)-a=15+5x
8x+15+5x-a=15+5x
8x+5x-5x+15-15=a
8x=a

Answer 4

8x=a