Which equation is the inverse of [tex]$5y + 4 = (x + 3)^2 + \frac{1}{2}$[/tex]?

A. [tex]y = \frac{1}{5} x^2 + \frac{6}{5} x + \frac{11}{10}[/tex]
B. [tex]y = 3 \pm \sqrt{5x + \frac{7}{2}}[/tex]
C. [tex]-5y - 4 = -(x + 3)^2 - \frac{1}{2}[/tex]
D. [tex]y = -3 \pm \sqrt{5x + \frac{7}{2}}[/tex]



Answer :

To determine which equation is the inverse of [tex]\( 5y + 4 = (x + 3)^2 + \frac{1}{2} \)[/tex], we need to manipulate the original equation and compare it to the given options.

First, let's solve the given equation for [tex]\( y \)[/tex]:

[tex]\[ 5y + 4 = (x + 3)^2 + \frac{1}{2} \][/tex]

Subtract 4 from both sides:

[tex]\[ 5y = (x + 3)^2 + \frac{1}{2} - 4 \][/tex]

Simplify the constant term on the right side:

[tex]\[ \frac{1}{2} - 4 = \frac{1}{2} - \frac{8}{2} = -\frac{7}{2} \][/tex]

Thus, the equation becomes:

[tex]\[ 5y = (x + 3)^2 - \frac{7}{2} \][/tex]

Divide both sides by 5 to solve for [tex]\( y \)[/tex]:

[tex]\[ y = \frac{(x + 3)^2 - \frac{7}{2}}{5} \][/tex]

Now let's consider the given options and see which one can be manipulated to match the above form.

1. [tex]\( y = \frac{1}{5}x^2 + \frac{6}{5}x + \frac{11}{10} \)[/tex]
2. [tex]\( y = 3 \pm \sqrt{5x + \frac{7}{2}} \)[/tex]
3. [tex]\( -5y - 4 = -(x + 3)^2 - \frac{1}{2} \)[/tex]
4. [tex]\( y = -3 \pm \sqrt{5x + \frac{7}{2}} \)[/tex]

Examining Option 3, we have:

[tex]\[ -5y - 4 = -(x + 3)^2 - \frac{1}{2} \][/tex]

If we multiply both sides by -1 to simplify, we get:

[tex]\[ 5y + 4 = (x + 3)^2 + \frac{1}{2} \][/tex]

This matches exactly the given equation. Therefore, the correct option is Option 3:

[tex]\[ -5 y - 4 = -(x + 3)^2-\frac{1}{2} \][/tex]

Hence, the inverse equation in the list is:

[tex]\[ -5y - 4 = -(x + 3)^2 - \frac{1}{2} \][/tex]

So the answer is:

[tex]\[ 3 \][/tex]