Which shows how to solve the equation [tex]\(-\frac{4}{5} x = 80\)[/tex] for [tex]\(x\)[/tex] in one step?

A. [tex]\(-\frac{4}{5}\left(\frac{5}{4}\right) x = 80\left(\frac{5}{4}\right)\)[/tex]

B. [tex]\(-\frac{4}{5}\left(-\frac{5}{4}\right) x = 80\left(-\frac{5}{4}\right)\)[/tex]

C. [tex]\(-\frac{4}{5}(-5) x = 80(-5)\)[/tex]

D. [tex]\(-\frac{4}{5}(5) x = 80(5)\)[/tex]



Answer :

To solve the equation [tex]\(-\frac{4}{5} x = 80\)[/tex] for [tex]\(x\)[/tex] in one step, we need to eliminate the coefficient of [tex]\(x\)[/tex] on the left-hand side of the equation.

The coefficient of [tex]\(x\)[/tex] is [tex]\(-\frac{4}{5}\)[/tex]. To isolate [tex]\(x\)[/tex], we multiply both sides of the equation by the reciprocal of [tex]\(-\frac{4}{5}\)[/tex].

The reciprocal of [tex]\(-\frac{4}{5}\)[/tex] is [tex]\(-\frac{5}{4}\)[/tex].

So, we multiply both sides of the equation by [tex]\(-\frac{5}{4}\)[/tex]:

[tex]\[ -\frac{4}{5} \left(-\frac{5}{4}\right) x = 80 \left(-\frac{5}{4}\right) \][/tex]

This simplifies as follows:

[tex]\[ (-\frac{4}{5}) \times (-\frac{5}{4}) = 1 \][/tex]

Thus, the left-hand side simplifies to [tex]\(x\)[/tex]:

[tex]\[ x = 80 \times (-\frac{5}{4}) \][/tex]

Therefore, after computing the right-hand side:

[tex]\[ x = -100 \][/tex]

Thus, the correct one-step way to solve the equation is:
[tex]\[ -\frac{4}{5}\left(-\frac{5}{4}\right) x=80\left(-\frac{5}{4}\right) \][/tex]