Solve 2x − 7 = 31

The solution of 2x − 7 = 31 is x = 19.

2x - 7 = 31\ \Rightarrow\ x = 19

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The lines y = 2x − 7 and y = 31 meet at x = 19. 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 subtraction, then the multiplication.
$2x - 7 = 31$
2
Add 7 to both sides:
$2x - 7 + 7 = 31 + 7 \ \Rightarrow\ 2x = 38$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{38}{2} \ \Rightarrow\ x = 19$
4
Check: put x = 19 back into the equation.
$2\cdot19 - 7 = 38 - 7 = 31 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 7 = 31\ \Rightarrow\ x = 19 \]
\[ 2x - 7 = 31 \]
\[ 2x - 7 + 7 = 31 + 7 \ \Rightarrow\ 2x = 38 \]
\[ \frac{2x}{2} = \frac{38}{2} \ \Rightarrow\ x = 19 \]
\[ 2\cdot19 - 7 = 38 - 7 = 31 \checkmark \]

Trying values of x in 2x − 7 = 31

x	2x − 7	Equals 31?
17	27	no
18	29	no
19	31	yes
20	33	no
21	35	no

Questions

What is x in 2x − 7 = 31?

The solution of 2x − 7 = 31 is x = 19.

How do you solve 2x − 7 = 31?

Add 7 to both sides to get 2x = 38, then divide both sides by 2 to get x = 19.

How do I check the answer?

Replace x by 19: 2(19) − 7 = 31, which is 31.

Solve 2x − 7 = 31

How to work it out

Trying values of x in 2x − 7 = 31

Questions

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