Solve 9x − 8 = −71

The solution of 9x − 8 = −71 is x = -7.

9x - 8 = -71\ \Rightarrow\ x = -7

Explain it step by step in chat Make a short video of it

The lines y = 9x − 8 and y = -71 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.
$9x - 8 = -71$
2
Add 8 to both sides:
$9x - 8 + 8 = -71 + 8 \ \Rightarrow\ 9x = -63$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{-63}{9} \ \Rightarrow\ x = -7$
4
Check: put x = -7 back into the equation.
$9\cdot(-7) - 8 = -63 - 8 = -71 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 8 = -71\ \Rightarrow\ x = -7 \]
\[ 9x - 8 = -71 \]
\[ 9x - 8 + 8 = -71 + 8 \ \Rightarrow\ 9x = -63 \]
\[ \frac{9x}{9} = \frac{-63}{9} \ \Rightarrow\ x = -7 \]
\[ 9\cdot(-7) - 8 = -63 - 8 = -71 \checkmark \]

Trying values of x in 9x − 8 = −71

x	9x − 8	Equals -71?
-9	-89	no
-8	-80	no
-7	-71	yes
-6	-62	no
-5	-53	no

Questions

What is x in 9x − 8 = −71?

The solution of 9x − 8 = −71 is x = -7.

How do you solve 9x − 8 = −71?

Add 8 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) − 8 = -71, which is -71.

Solve 9x − 8 = −71

How to work it out

Trying values of x in 9x − 8 = −71

Questions

Similar equations