Solve 2x + 11 = 51

The solution of 2x + 11 = 51 is x = 20.

2x + 11 = 51\ \Rightarrow\ x = 20

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The lines y = 2x + 11 and y = 51 meet at x = 20. 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.
$2x + 11 = 51$
2
Subtract 11 from both sides:
$2x + 11 - 11 = 51 - 11 \ \Rightarrow\ 2x = 40$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{40}{2} \ \Rightarrow\ x = 20$
4
Check: put x = 20 back into the equation.
$2\cdot20 + 11 = 40 + 11 = 51 \checkmark$

LaTeX source of the formulas on this page

\[ 2x + 11 = 51\ \Rightarrow\ x = 20 \]
\[ 2x + 11 = 51 \]
\[ 2x + 11 - 11 = 51 - 11 \ \Rightarrow\ 2x = 40 \]
\[ \frac{2x}{2} = \frac{40}{2} \ \Rightarrow\ x = 20 \]
\[ 2\cdot20 + 11 = 40 + 11 = 51 \checkmark \]

Trying values of x in 2x + 11 = 51

x	2x + 11	Equals 51?
18	47	no
19	49	no
20	51	yes
21	53	no
22	55	no

Questions

What is x in 2x + 11 = 51?

The solution of 2x + 11 = 51 is x = 20.

How do you solve 2x + 11 = 51?

Subtract 11 from both sides to get 2x = 40, then divide both sides by 2 to get x = 20.

How do I check the answer?

Replace x by 20: 2(20) + 11 = 51, which is 51.

Solve 2x + 11 = 51

How to work it out

Trying values of x in 2x + 11 = 51

Questions

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