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Solve 7x + 7 = 21

The solution of 7x + 7 = 21 is x = 2.

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The lines y = 7x + 7 and y = 21 meet at x = 2-4-22468-20204060x = 2y = 7x + 7y = 21
The lines y = 7x + 7 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.

    7x+7=217x + 7 = 21
  2. 2

    Subtract 7 from both sides:

    7x+7−7=21−7 ⇒ 7x=147x + 7 - 7 = 21 - 7 \ \Rightarrow\ 7x = 14
  3. 3

    Divide both sides by 7:

    7x7=147 ⇒ x=2\frac{7x}{7} = \frac{14}{7} \ \Rightarrow\ x = 2
  4. 4

    Check: put x = 2 back into the equation.

    7⋅2+7=14+7=21✓7\cdot2 + 7 = 14 + 7 = 21 \checkmark
LaTeX source of the formulas on this page
\[ 7x + 7 = 21\ \Rightarrow\ x = 2 \]
\[ 7x + 7 = 21 \]
\[ 7x + 7 - 7 = 21 - 7 \ \Rightarrow\ 7x = 14 \]
\[ \frac{7x}{7} = \frac{14}{7} \ \Rightarrow\ x = 2 \]
\[ 7\cdot2 + 7 = 14 + 7 = 21 \checkmark \]

Trying values of x in 7x + 7 = 21

x7x + 7Equals 21?
07no
114no
221yes
328no
435no

Questions

What is x in 7x + 7 = 21?

The solution of 7x + 7 = 21 is x = 2.

How do you solve 7x + 7 = 21?

Subtract 7 from both sides to get 7x = 14, then divide both sides by 7 to get x = 2.

How do I check the answer?

Replace x by 2: 7(2) + 7 = 21, which is 21.

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    Solve 7x + 7 = 21: x = 2 (steps and check) | WordGPT