Solve 2x + 11 = 31

The solution of 2x + 11 = 31 is x = 10.

2x + 11 = 31\ \Rightarrow\ x = 10

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The lines y = 2x + 11 and y = 31 meet at x = 10. The solution of the equation is the x-coordinate of the point where the two sides are equal.

How to work it out

1
The goal is to get x alone. Undo the operations in the opposite order: first the addition, then the multiplication.
$2x + 11 = 31$
2
Subtract 11 from both sides:
$2x + 11 - 11 = 31 - 11 \ \Rightarrow\ 2x = 20$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{20}{2} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$2\cdot10 + 11 = 20 + 11 = 31 \checkmark$

LaTeX source of the formulas on this page

\[ 2x + 11 = 31\ \Rightarrow\ x = 10 \]
\[ 2x + 11 = 31 \]
\[ 2x + 11 - 11 = 31 - 11 \ \Rightarrow\ 2x = 20 \]
\[ \frac{2x}{2} = \frac{20}{2} \ \Rightarrow\ x = 10 \]
\[ 2\cdot10 + 11 = 20 + 11 = 31 \checkmark \]

Trying values of x in 2x + 11 = 31

x	2x + 11	Equals 31?
8	27	no
9	29	no
10	31	yes
11	33	no
12	35	no

Questions

What is x in 2x + 11 = 31?

The solution of 2x + 11 = 31 is x = 10.

How do you solve 2x + 11 = 31?

Subtract 11 from both sides to get 2x = 20, then divide both sides by 2 to get x = 10.

How do I check the answer?

Replace x by 10: 2(10) + 11 = 31, which is 31.

Solve 2x + 11 = 31

How to work it out

Trying values of x in 2x + 11 = 31

Questions

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