Solve 11x − 1 = −78

The solution of 11x − 1 = −78 is x = -7.

11x - 1 = -78\ \Rightarrow\ x = -7

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The lines y = 11x − 1 and y = -78 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.
$11x - 1 = -78$
2
Add 1 to both sides:
$11x - 1 + 1 = -78 + 1 \ \Rightarrow\ 11x = -77$
3
Divide both sides by 11:
$\frac{11x}{11} = \frac{-77}{11} \ \Rightarrow\ x = -7$
4
Check: put x = -7 back into the equation.
$11\cdot(-7) - 1 = -77 - 1 = -78 \checkmark$

LaTeX source of the formulas on this page

\[ 11x - 1 = -78\ \Rightarrow\ x = -7 \]
\[ 11x - 1 = -78 \]
\[ 11x - 1 + 1 = -78 + 1 \ \Rightarrow\ 11x = -77 \]
\[ \frac{11x}{11} = \frac{-77}{11} \ \Rightarrow\ x = -7 \]
\[ 11\cdot(-7) - 1 = -77 - 1 = -78 \checkmark \]

Trying values of x in 11x − 1 = −78

x	11x − 1	Equals -78?
-9	-100	no
-8	-89	no
-7	-78	yes
-6	-67	no
-5	-56	no

Questions

What is x in 11x − 1 = −78?

The solution of 11x − 1 = −78 is x = -7.

How do you solve 11x − 1 = −78?

Add 1 to both sides to get 11x = -77, then divide both sides by 11 to get x = -7.

How do I check the answer?

Replace x by -7: 11(-7) − 1 = -78, which is -78.

Solve 11x − 1 = −78

How to work it out

Trying values of x in 11x − 1 = −78

Questions

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