Solve 9x − 7 = −70

The solution of 9x − 7 = −70 is x = -7.

9x - 7 = -70\ \Rightarrow\ x = -7

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The lines y = 9x − 7 and y = -70 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.
$9x - 7 = -70$
2
Add 7 to both sides:
$9x - 7 + 7 = -70 + 7 \ \Rightarrow\ 9x = -63$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{-63}{9} \ \Rightarrow\ x = -7$
4
Check: put x = -7 back into the equation.
$9\cdot(-7) - 7 = -63 - 7 = -70 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 7 = -70\ \Rightarrow\ x = -7 \]
\[ 9x - 7 = -70 \]
\[ 9x - 7 + 7 = -70 + 7 \ \Rightarrow\ 9x = -63 \]
\[ \frac{9x}{9} = \frac{-63}{9} \ \Rightarrow\ x = -7 \]
\[ 9\cdot(-7) - 7 = -63 - 7 = -70 \checkmark \]

Trying values of x in 9x − 7 = −70

x	9x − 7	Equals -70?
-9	-88	no
-8	-79	no
-7	-70	yes
-6	-61	no
-5	-52	no

Questions

What is x in 9x − 7 = −70?

The solution of 9x − 7 = −70 is x = -7.

How do you solve 9x − 7 = −70?

Add 7 to both sides to get 9x = -63, then divide both sides by 9 to get x = -7.

How do I check the answer?

Replace x by -7: 9(-7) − 7 = -70, which is -70.

Solve 9x − 7 = −70

How to work it out

Trying values of x in 9x − 7 = −70

Questions

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