Solve 7x − 15 = 34

The solution of 7x − 15 = 34 is x = 7.

7x - 15 = 34\ \Rightarrow\ x = 7

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The lines y = 7x − 15 and y = 34 meet at x = 7. 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.
$7x - 15 = 34$
2
Add 15 to both sides:
$7x - 15 + 15 = 34 + 15 \ \Rightarrow\ 7x = 49$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{49}{7} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$7\cdot7 - 15 = 49 - 15 = 34 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 15 = 34\ \Rightarrow\ x = 7 \]
\[ 7x - 15 = 34 \]
\[ 7x - 15 + 15 = 34 + 15 \ \Rightarrow\ 7x = 49 \]
\[ \frac{7x}{7} = \frac{49}{7} \ \Rightarrow\ x = 7 \]
\[ 7\cdot7 - 15 = 49 - 15 = 34 \checkmark \]

Trying values of x in 7x − 15 = 34

x	7x − 15	Equals 34?
5	20	no
6	27	no
7	34	yes
8	41	no
9	48	no

Questions

What is x in 7x − 15 = 34?

The solution of 7x − 15 = 34 is x = 7.

How do you solve 7x − 15 = 34?

Add 15 to both sides to get 7x = 49, then divide both sides by 7 to get x = 7.

How do I check the answer?

Replace x by 7: 7(7) − 15 = 34, which is 34.

Solve 7x − 15 = 34

How to work it out

Trying values of x in 7x − 15 = 34

Questions

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