Solve 8x + 3 = 131

The solution of 8x + 3 = 131 is x = 16.

8x + 3 = 131\ \Rightarrow\ x = 16

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The lines y = 8x + 3 and y = 131 meet at x = 16. 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.
$8x + 3 = 131$
2
Subtract 3 from both sides:
$8x + 3 - 3 = 131 - 3 \ \Rightarrow\ 8x = 128$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{128}{8} \ \Rightarrow\ x = 16$
4
Check: put x = 16 back into the equation.
$8\cdot16 + 3 = 128 + 3 = 131 \checkmark$

LaTeX source of the formulas on this page

\[ 8x + 3 = 131\ \Rightarrow\ x = 16 \]
\[ 8x + 3 = 131 \]
\[ 8x + 3 - 3 = 131 - 3 \ \Rightarrow\ 8x = 128 \]
\[ \frac{8x}{8} = \frac{128}{8} \ \Rightarrow\ x = 16 \]
\[ 8\cdot16 + 3 = 128 + 3 = 131 \checkmark \]

Trying values of x in 8x + 3 = 131

x	8x + 3	Equals 131?
14	115	no
15	123	no
16	131	yes
17	139	no
18	147	no

Questions

What is x in 8x + 3 = 131?

The solution of 8x + 3 = 131 is x = 16.

How do you solve 8x + 3 = 131?

Subtract 3 from both sides to get 8x = 128, then divide both sides by 8 to get x = 16.

How do I check the answer?

Replace x by 16: 8(16) + 3 = 131, which is 131.

Solve 8x + 3 = 131

How to work it out

Trying values of x in 8x + 3 = 131

Questions

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