Solve 7x − 8 = −1

The solution of 7x − 8 = −1 is x = 1.

7x - 8 = -1\ \Rightarrow\ x = 1

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The lines y = 7x − 8 and y = -1 meet at x = 1. 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.
$7x - 8 = -1$
2
Add 8 to both sides:
$7x - 8 + 8 = -1 + 8 \ \Rightarrow\ 7x = 7$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{7}{7} \ \Rightarrow\ x = 1$
4
Check: put x = 1 back into the equation.
$7\cdot1 - 8 = 7 - 8 = -1 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 8 = -1\ \Rightarrow\ x = 1 \]
\[ 7x - 8 = -1 \]
\[ 7x - 8 + 8 = -1 + 8 \ \Rightarrow\ 7x = 7 \]
\[ \frac{7x}{7} = \frac{7}{7} \ \Rightarrow\ x = 1 \]
\[ 7\cdot1 - 8 = 7 - 8 = -1 \checkmark \]

Trying values of x in 7x − 8 = −1

x	7x − 8	Equals -1?
-1	-15	no
0	-8	no
1	-1	yes
2	6	no
3	13	no

Questions

What is x in 7x − 8 = −1?

The solution of 7x − 8 = −1 is x = 1.

How do you solve 7x − 8 = −1?

Add 8 to both sides to get 7x = 7, then divide both sides by 7 to get x = 1.

How do I check the answer?

Replace x by 1: 7(1) − 8 = -1, which is -1.

Solve 7x − 8 = −1

How to work it out

Trying values of x in 7x − 8 = −1

Questions

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