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5x-6=2x+9 solve and Check the solution

User Shiva Nandan
by
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1 Answer

5 votes
5 votes

Answer:

x = 5

Explanation:

Take your starting equation:

5x - 6 = 2x + 9

Your first step should be to isolate the variable, X, by having it on only one side of the equation. This can be done by subtracting one of the X values (either 5x or 2x) from either side, but I recommend the side with 2x since it's a smaller value and won't result in a negative.

(This is the right side of the equation)

2x + 9

- 2x

= 9

We need to do the same thing on the other side of the equation too, to balance both sides:

(This is the left side of the equation)

5x - 6

- 2x

= 3x - 6

This is our equation now:

3x - 6 = 9

The next step is to isolate X further by removing any constants (regular numbers) from the side with X. Since the constant on that side is -6, we need to add 6 to that side so that it's cancelled out, and do the same on the other side to balance.

(This is the left side of the equation)

3x - 6

+ 6

= 3x

And now for the other side:

(This is the right side of the equation)

9

+ 6

= 15

This is our current equation:

3x = 15

The final step is to get X completely isolated. X is being multiplied by 3, so we need to divide both sides of the equation by 3 to finally get the value of X.

(This is the left side of the equation)

3x

÷ 3

= x

And now for the other side:

(This is the right side of the equation)

15

÷ 3

= 5

Our final equation:

x = 5

We can check our answer by taking the final X value, 5, and inserting it into our beginning equation.

This is the beginning equation, as a reminder:

5x - 6 = 2x + 9

Replace all instances of X with its value, 5:

(5 · 5) - 6 = (2 · 5) + 9

After simplifying, the result is:

19 = 19, which means the X value is correct.

User Jason Slocomb
by
2.7k points