Question

3x+9=5x+21

What is x

Answer 1

X = -6

1. 3x + 9 = 5x + 21

2. Subtract -5x from both sides

3x + 9 - 5x = 5x + 21 - 5x

3.-2x + 9 = 21

4. Subtract 9 from both sides

-2x + 9 - 9 = 21 - 9

5.-2x = 12

6. Divide both sides by -2

-2x/-2 = 12/-2

7. x= -6

Answer 2

Answer:

Simplifying
3x + 9 = 5x + 21

Reorder the terms:
9 + 3x = 5x + 21

Reorder the terms:
9 + 3x = 21 + 5x

Solving
9 + 3x = 21 + 5x

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-5x' to each side of the equation.
9 + 3x + -5x = 21 + 5x + -5x

Combine like terms: 3x + -5x = -2x
9 + -2x = 21 + 5x + -5x

Combine like terms: 5x + -5x = 0
9 + -2x = 21 + 0
9 + -2x = 21

Add '-9' to each side of the equation.
9 + -9 + -2x = 21 + -9

Combine like terms: 9 + -9 = 0
0 + -2x = 21 + -9
-2x = 21 + -9

Combine like terms: 21 + -9 = 12
-2x = 12

Divide each side by '-2'.
x = -6

Simplifying
x = -6

God bless you and I hope this helps :)