Solve 7x − 1 = 104

The solution of 7x − 1 = 104 is x = 15.

7x - 1 = 104\ \Rightarrow\ x = 15

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The lines y = 7x − 1 and y = 104 meet at x = 15. 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.
$7x - 1 = 104$
2
Add 1 to both sides:
$7x - 1 + 1 = 104 + 1 \ \Rightarrow\ 7x = 105$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{105}{7} \ \Rightarrow\ x = 15$
4
Check: put x = 15 back into the equation.
$7\cdot15 - 1 = 105 - 1 = 104 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 1 = 104\ \Rightarrow\ x = 15 \]
\[ 7x - 1 = 104 \]
\[ 7x - 1 + 1 = 104 + 1 \ \Rightarrow\ 7x = 105 \]
\[ \frac{7x}{7} = \frac{105}{7} \ \Rightarrow\ x = 15 \]
\[ 7\cdot15 - 1 = 105 - 1 = 104 \checkmark \]

Trying values of x in 7x − 1 = 104

x	7x − 1	Equals 104?
13	90	no
14	97	no
15	104	yes
16	111	no
17	118	no

Questions

What is x in 7x − 1 = 104?

The solution of 7x − 1 = 104 is x = 15.

How do you solve 7x − 1 = 104?

Add 1 to both sides to get 7x = 105, then divide both sides by 7 to get x = 15.

How do I check the answer?

Replace x by 15: 7(15) − 1 = 104, which is 104.

Solve 7x − 1 = 104

How to work it out

Trying values of x in 7x − 1 = 104

Questions

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