Solve −9 − 5x = −39
Linear equation, worked out line by line the way a teacher would write it.
Answer
| Solution | x = 6 |
Step-by-step solution
5 steps-
1 Given-9 - 5 x = -39
Solve for x.
-
2 Add 9 to both sides
An equation stays true as long as you do the same thing to both sides, like adding the same weight to both pans of a balance. Adding or subtracting the same amount on both sides moves a term to the other side, where it appears with the opposite sign.
- 5 x = -30Move the constant terms to the right.
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3 Divide both sides by -5
Dividing both sides by -5 undoes the multiplication by -5, so the variable is left on its own. Both sides change in the same way, so the equation stays true (dividing by 0 is the one thing that is never allowed).
x = \frac{-30}{-5} -
4 Simplifyx = 6
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5 Check\begin{aligned}x = 6:\quad -39 = -39\quad\checkmark\end{aligned}
Substituting each solution back makes both sides equal.
Check by substitution
| x | Left side | Right side | |
|---|---|---|---|
| 6 | −39 | −39 | ✓ |
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