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Solve 12x + 9 = 213

The solution of 12x + 9 = 213 is x = 17.

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The lines y = 12x + 9 and y = 213 meet at x = 17121416182022140160180200220240260280300x = 17y = 12x + 9y = 213
The lines y = 12x + 9 and y = 213 meet at x = 17. The solution of the equation is the x-coordinate of the point where the two sides are equal.

How to work it out

  1. 1

    The goal is to get x alone. Undo the operations in the opposite order: first the addition, then the multiplication.

    12x+9=21312x + 9 = 213
  2. 2

    Subtract 9 from both sides:

    12x+9−9=213−9 ⇒ 12x=20412x + 9 - 9 = 213 - 9 \ \Rightarrow\ 12x = 204
  3. 3

    Divide both sides by 12:

    12x12=20412 ⇒ x=17\frac{12x}{12} = \frac{204}{12} \ \Rightarrow\ x = 17
  4. 4

    Check: put x = 17 back into the equation.

    12⋅17+9=204+9=213✓12\cdot17 + 9 = 204 + 9 = 213 \checkmark
LaTeX source of the formulas on this page
\[ 12x + 9 = 213\ \Rightarrow\ x = 17 \]
\[ 12x + 9 = 213 \]
\[ 12x + 9 - 9 = 213 - 9 \ \Rightarrow\ 12x = 204 \]
\[ \frac{12x}{12} = \frac{204}{12} \ \Rightarrow\ x = 17 \]
\[ 12\cdot17 + 9 = 204 + 9 = 213 \checkmark \]

Trying values of x in 12x + 9 = 213

x12x + 9Equals 213?
15189no
16201no
17213yes
18225no
19237no

Questions

What is x in 12x + 9 = 213?

The solution of 12x + 9 = 213 is x = 17.

How do you solve 12x + 9 = 213?

Subtract 9 from both sides to get 12x = 204, then divide both sides by 12 to get x = 17.

How do I check the answer?

Replace x by 17: 12(17) + 9 = 213, which is 213.

Similar equations

    Solve 12x + 9 = 213: x = 17 (steps and check) | WordGPT