Solve 9x + 3 = −69

The solution of 9x + 3 = −69 is x = -8.

9x + 3 = -69\ \Rightarrow\ x = -8

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The lines y = 9x + 3 and y = -69 meet at x = -8. 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.
$9x + 3 = -69$
2
Subtract 3 from both sides:
$9x + 3 - 3 = -69 - 3 \ \Rightarrow\ 9x = -72$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{-72}{9} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$9\cdot(-8) + 3 = -72 + 3 = -69 \checkmark$

LaTeX source of the formulas on this page

\[ 9x + 3 = -69\ \Rightarrow\ x = -8 \]
\[ 9x + 3 = -69 \]
\[ 9x + 3 - 3 = -69 - 3 \ \Rightarrow\ 9x = -72 \]
\[ \frac{9x}{9} = \frac{-72}{9} \ \Rightarrow\ x = -8 \]
\[ 9\cdot(-8) + 3 = -72 + 3 = -69 \checkmark \]

Trying values of x in 9x + 3 = −69

x	9x + 3	Equals -69?
-10	-87	no
-9	-78	no
-8	-69	yes
-7	-60	no
-6	-51	no

Questions

What is x in 9x + 3 = −69?

The solution of 9x + 3 = −69 is x = -8.

How do you solve 9x + 3 = −69?

Subtract 3 from both sides to get 9x = -72, then divide both sides by 9 to get x = -8.

How do I check the answer?

Replace x by -8: 9(-8) + 3 = -69, which is -69.

Solve 9x + 3 = −69

How to work it out

Trying values of x in 9x + 3 = −69

Questions

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