Solve 10x + 9 = −1

The solution of 10x + 9 = −1 is x = -1.

10x + 9 = -1\ \Rightarrow\ x = -1

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The lines y = 10x + 9 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 addition, then the multiplication.
$10x + 9 = -1$
2
Subtract 9 from both sides:
$10x + 9 - 9 = -1 - 9 \ \Rightarrow\ 10x = -10$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{-10}{10} \ \Rightarrow\ x = -1$
4
Check: put x = -1 back into the equation.
$10\cdot(-1) + 9 = -10 + 9 = -1 \checkmark$

LaTeX source of the formulas on this page

\[ 10x + 9 = -1\ \Rightarrow\ x = -1 \]
\[ 10x + 9 = -1 \]
\[ 10x + 9 - 9 = -1 - 9 \ \Rightarrow\ 10x = -10 \]
\[ \frac{10x}{10} = \frac{-10}{10} \ \Rightarrow\ x = -1 \]
\[ 10\cdot(-1) + 9 = -10 + 9 = -1 \checkmark \]

Trying values of x in 10x + 9 = −1

x	10x + 9	Equals -1?
-3	-21	no
-2	-11	no
-1	-1	yes
0	9	no
1	19	no

Questions

What is x in 10x + 9 = −1?

The solution of 10x + 9 = −1 is x = -1.

How do you solve 10x + 9 = −1?

Subtract 9 from both sides to get 10x = -10, then divide both sides by 10 to get x = -1.

How do I check the answer?

Replace x by -1: 10(-1) + 9 = -1, which is -1.

Solve 10x + 9 = −1

How to work it out

Trying values of x in 10x + 9 = −1

Questions

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