Solve 0.4x + 1.2 = 0.4
Linear equation, worked out line by line the way a teacher would write it.
Answer
| Solution | x = −2 |
Step-by-step solution
5 steps-
1 Given0.4 x + 1.2 = 0.4
Solve for x.
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2 Subtract 1.2 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.
0.4 x = -0.8Move the constant terms to the right.
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3 Divide both sides by 0.4
Dividing both sides by 0.4 undoes the multiplication by 0.4, 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{-0.8}{0.4} -
4 Simplifyx = -2
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5 Check\begin{aligned}x = -2:\quad 0.4 = 0.4\quad\checkmark\end{aligned}
Substituting each solution back makes both sides equal.
Check by substitution
| x | Left side | Right side | |
|---|---|---|---|
| −2 | 0.4 | 0.4 | ✓ |
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