WordGPT

Solve 3x + 15 = 21

The solution of 3x + 15 = 21 is x = 2.

Explain it step by step in chatMake a short video of it
The lines y = 3x + 15 and y = 21 meet at x = 2-4-22468510152025303540x = 2y = 3x + 15y = 21
The lines y = 3x + 15 and y = 21 meet at x = 2. 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.

    3x+15=213x + 15 = 21
  2. 2

    Subtract 15 from both sides:

    3x+15−15=21−15 ⇒ 3x=63x + 15 - 15 = 21 - 15 \ \Rightarrow\ 3x = 6
  3. 3

    Divide both sides by 3:

    3x3=63 ⇒ x=2\frac{3x}{3} = \frac{6}{3} \ \Rightarrow\ x = 2
  4. 4

    Check: put x = 2 back into the equation.

    3⋅2+15=6+15=21✓3\cdot2 + 15 = 6 + 15 = 21 \checkmark
LaTeX source of the formulas on this page
\[ 3x + 15 = 21\ \Rightarrow\ x = 2 \]
\[ 3x + 15 = 21 \]
\[ 3x + 15 - 15 = 21 - 15 \ \Rightarrow\ 3x = 6 \]
\[ \frac{3x}{3} = \frac{6}{3} \ \Rightarrow\ x = 2 \]
\[ 3\cdot2 + 15 = 6 + 15 = 21 \checkmark \]

Trying values of x in 3x + 15 = 21

x3x + 15Equals 21?
015no
118no
221yes
324no
427no

Questions

What is x in 3x + 15 = 21?

The solution of 3x + 15 = 21 is x = 2.

How do you solve 3x + 15 = 21?

Subtract 15 from both sides to get 3x = 6, then divide both sides by 3 to get x = 2.

How do I check the answer?

Replace x by 2: 3(2) + 15 = 21, which is 21.

Similar equations

    Solve 3x + 15 = 21: x = 2 (steps and check) | WordGPT