19) Find the variation constant and the equation of variation.

Given: [tex]\( y \)[/tex] varies inversely as [tex]\( x \)[/tex], and [tex]\( y = 6 \)[/tex] when [tex]\( x = 7 \)[/tex].



Answer :

To solve this problem, we need to understand the concept of inverse variation. When we say that [tex]\( y \)[/tex] varies inversely as [tex]\( x \)[/tex], it means that [tex]\( y \)[/tex] is inversely proportional to [tex]\( x \)[/tex]. This can be mathematically represented by the equation:

[tex]\[ y = \frac{k}{x} \][/tex]

Here, [tex]\( k \)[/tex] is the variation constant that we need to determine.

We are given the following information:
- [tex]\( y = 6 \)[/tex]
- [tex]\( x = 7 \)[/tex]

To find the variation constant [tex]\( k \)[/tex], we can substitute the given values of [tex]\( y \)[/tex] and [tex]\( x \)[/tex] into the inverse variation equation:

[tex]\[ 6 = \frac{k}{7} \][/tex]

To solve for [tex]\( k \)[/tex], we multiply both sides of the equation by 7:

[tex]\[ 6 \times 7 = k \][/tex]

[tex]\[ k = 42 \][/tex]

So, the variation constant [tex]\( k \)[/tex] is 42.

Next, we need to write the equation that represents this inverse variation. Using the value of [tex]\( k \)[/tex] we just found and substituting it back into the inverse variation equation:

[tex]\[ y = \frac{42}{x} \][/tex]

Therefore, the equation of variation is:

[tex]\[ y = \frac{42}{x} \][/tex]

In summary:
- The variation constant is [tex]\( k = 42 \)[/tex].
- The equation of variation is [tex]\( y = \frac{42}{x} \)[/tex].