Solve 3 − 2x = −7
Linear equation, worked out line by line the way a teacher would write it.
Answer
| Solution | x = 5 |
Step-by-step solution
5 steps-
1 Given3 - 2 x = -7
Solve for x.
-
2 Subtract 3 from 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.
- 2 x = -10Move the constant terms to the right.
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3 Divide both sides by -2
Dividing both sides by -2 undoes the multiplication by -2, 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{-10}{-2} -
4 Simplifyx = 5
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5 Check\begin{aligned}x = 5:\quad -7 = -7\quad\checkmark\end{aligned}
Substituting each solution back makes both sides equal.
Check by substitution
| x | Left side | Right side | |
|---|---|---|---|
| 5 | −7 | −7 | ✓ |
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