Respuesta :

Supposing you want this equation to be solved for a: we start with

[tex]-\dfrac{a}{5}+21=23[/tex]

Subtract 21 from both sides:

[tex]-\dfrac{a}{5}=2[/tex]

Multiply both sides by 5:

[tex]-a=10[/tex]

Change sign to both sides:

[tex]a=-10[/tex]
First substitute 21 to the right side
Then,
-1/5a=23-21
-1/5a=2
Now,take -1/5 to the other side
a=2(-5)
a=-10
Therefore,a should be substituted by -10 to make them equal.